1. Предложен и апробирован прецизио

1. Предложен и апробирован прецизионный метод измерения магнитокалорического эффекта (МКЭ), основанный на измерении амплитуды осцилляций температуры образца в переменном магнитном поле. Созданная на этой основе полностью автоматизированная экспериментальная установка для измерения МКЭ не имеет аналогов в мире и обладает рядом существенных преимуществ, недоступных другим методикам:
- высокая точность (ΔT ~0.001 K) измерения МКЭ, позволяющая проводить исследования в слабых магнитных полях. Это означает, что данную методику можно также использовать для диагностики фазового состава ферро-антиферромагнетиков.
- возможность исследования маломерных образцов (микропровода, ленты)
- малые энергетические и временные затраты.
- возможность исследования частотной зависимости МКЭ;
Впервые проведены прямые измерения МКЭ в ленточных образцах сплавов Гейслера Ni50Mn40In10 и Ni50Mn37Sn13, перспективных для применения в технологии магнитного охлаждения. В исследованных составах обнаружены прямой и обратный магнитокалорический эффекты, связанные с магнитными (парамагнетик – ферромагнетик, ферри – антиферромагнетик) и структурными (аустенит – мартенсит) фазовыми переходами.
Applied Physics Letters 97, 212505 (2010), Письма в ЖЭТФ 90, 736-739 (2009).

2. В сплаве Fe48Rh52 обнаружено рекордное значение магнитокалорического эффекта (ΔT = 20 K в переменном магнитном поле амплитудой ΔB=8 Тл и частотой 0.13 Гц). Показано, что в этом материале

3. Предложен метод увеличения охлаждающей эффективности существующих магнитокалорических материалов посредством изготовления сэндвичей из двух или более материалов с близкими магнитокалорическими свойствами. Метод был апробирован на манганитах La0.7Ca0.3MnO3 (O16) и La0.7Ca0.3MnO3 (O18). Прямыми и косвенными измерениями магнитокалорического эффекта было показано, что по сравнению с исходными материалами, охлаждающая эффективность сэндвича La0.7Ca0.3MnO3(O16)+La0.7Ca0.3MnO3(O18) возрастает примерно на 20 %.
Applied Physics Letters 101, 172401 (2012)

4. Исследование теплофизических свойства катион-упорядоченных манганитов NdBaMn2O6 и PrBaMn2O6 показало, что:
- поведение магнитокалорического эффекта в NdBaMn2O6 в области фазового перехода в этом составе носит аномальный характер. В области слабых магнитных полей (до 200 Э) вблизи магнитоструктурного фазового перехода наблюдаются как прямой, так и обратный магнитокалорические эффекты. В магнитном поле 11 кЭ прямой и обратный эффекты наблюдаются только в режиме охлаждения, в то время как в режиме нагрева прямой эффект не наблюдается. Такое поведение МКЭ объясняется замораживанием основного антиферромагнитного состояния в области промежуточных полей.
Solid State Communications 151, 1820–1823 (2011).

5. Исследования магнитокалорического эффекта в манганитах La1-xKxMnO3 тремя независимыми методами - методом модуляции магнитного поля, путем анализа данных по теплоемкости в магнитном поле и без него и классическим прямым методом показали, что
- магнитополевая зависимость МКЭ в слабых магнитных полях строго следует предсказаниям теории среднего поля при учете зависимости теплоемкости от магнитного поля, а точное измерение МКЭ в слабых магнитных полях является надежным способом определения T_C магнитных материалов.
- полученные разными методами значения МКЭ в La1-xKxMnO3 существенно отличаются друг от друга, что указывает на необходимость разносторонних оценок эффекта для получения достоверных данных.
- что в оптимально допированных образцах величина МКЭ достигает величин, сравнимых с данными для гадолиния, а максимум эффекта наблюдается вблизи комнатных температур, что делает их альтернативными материалами для технологии магнитного охлаждения.
ЖЭТФ 139, 529-538 (2011), Physica B 406, 885-889 (2011).

6. Исследовано влияние размера гранул на магнитные и магнитокалорические свойства керамических образцов манганита La0.5Ca0.5MnO3. На температурной зависимости магнитокалорического эффекта обнаружены аномалии, свидетельствующие о сосуществовании ферромагнитной металлической и антиферромагнитной зарядово-упорядоченной фаз ниже TC. Показано, что уменьшение размера гранул до 90 nm приводит к полному подавлению антиферромагнитной зарядово-упорядоченной фазы.
Journal of Applied Physics 113, 123904 (2013).

7. Совместно с коллегами из Челябинского государственного университета теоретически и экспериментально исследован магнитокалорический эффект в сплавах Гейслера Ni-Mn-X (X=Ga, In). Проведено сравнение рассчитанного методом Монте-Карло значения МКЭ с экспериментальными значениями, полученными путем прямых измерений. Получено удовлетворительное согласие рассчитанных и измеренных значений МКЭ в указанных сплавах.
Journal of Physics D: Applied Physics 44, 064012 (2011).

8. В ленточных образцах сплава Гейслера Ni50.3Mn36.5Sn13.2 в области магнитоструктурного фазового перехода обнаружена сильная зависимость МКЭ от времени – с течением времени величина эффекта уменьшается, в пределе стремясь к нулю. Если обнаружится, что МКЭ и в других материалах в области магнитоструктурных переходов также зависит от времени, поиски оптимальных материалов для твердотельных магнитных холодильников нужно будет вести в совершенно ином направлении.

9. Проведены прямые измерения магнитокалорического эффекта микропроводов сплавов Гейслера, покрытых стеклом. После отжига микропровода проявляют ферромагнитные свойства при комнатных температурах. Максимальная величина эффекта достигает ΔT=0.22 K при изменении магнитного поля ΔH=18 кЭ. Продемонстрирована возможность изготовления магнетокалорических материалов для магнитного охлаждения в форме микропроводов, покрытых стеклом. С точки зрения практического применения, такие материалы м

Результаты (английский) 1:

1. Proposed and tested precision method for measurement of magnitokaloričeskogo effect (FEM) based on the measurement of the amplitude of the oscillations of temperature sample in an alternating magnetic field. Established on this basis, fully automated measuring experimental FEA has no analogues in the world and has a number of advantages that are not available to other methods:-high accuracy (ΔT ~ 0.001 K) dimension FEM, allowing you to conduct research in weak magnetic fields. This means that you can also use this technique for the diagnosis of the phase composition of Ferro-Ferromagnetism.-possibility to study small samples (microwire, tapes)-small energy and time costs.-possibility to study frequency dependence of FEA;First direct measurements of the FEA in tape samples alloys Ni50Mn40In10 and Ni50Mn37Sn13 Geissler, promising for use in magnetic refrigeration technology. In the studied convoys found direct and reverse magnitokaloričeskij effects associated with magnetic (paramagnetik-ferromagnetic, Ferri-antiferromagnetik) and structure (austenite-martensite) phase transitions.Applied Physics Letters 97, 212,505 (2010), jetp letters 90, 736-739 (2009).2. In the alloy Fe48Rh52 discovered a record value of magnitokaloričeskogo effect (ΔT = 20 K in a variable magnetic field amplitude ΔB = 8 T and 0.13 frequency Hz). It is shown that in this material 3. The method of increasing the cooling efficiency of the existing magnitokaloričeskih materials by manufacture of sandwiches of two or more materials with similar properties magnitokaloričeskimi. The method was tested on manganitah La 0.7 Ca 0.3 MnO3 (O16) and La 0.7 Ca 0.3 MnO3 (O18). Direct and indirect measurements of magnitokaloričeskogo effects it has been shown that compared to the starting materials, cooling efficiency sandwich La 0.7 Ca 0.3 (O16) MnO3 + La 0.7 Ca 0.3 MnO3 (O18) increases by about 20%.Applied Physics Letters, 101 172,401 (2012)4. Study of the thermophysical properties of cation-ordered manganites NdBaMn2O6 and PrBaMn2O6 showed that: -behavior of magnitokaloričeskogo effect in NdBaMn2O6 in the area of phase transition in this composition is abnormal in nature. In the field of weak magnetic fields (up to 200) near magnitostrukturnogo phase transition observed both direct and reverse magnitokaloričeskie effects. In the magnetic field 11 EC direct and reverse effects are observed only in cooling mode, while in heat mode the direct effect is not observed. This behavior is due to the freezing of the main FEA Antiferromagnetic State of intermediate fields. Solid State Communications 151, 1820-1823 (2011). 5. Study of magnitokaloričeskogo effect in manganitah La1-xKxMnO3 three independent methods of magnetic field modulation method, by analysing data on specific heat in magnetic field and without it and the classic direct method showed that -magnitopolevaâ dependence of the FEA in weak magnetic fields strictly follows the predictions of the theory of the middle of the field while taking into account the dependence of the heat capacity of the magnetic field, and the exact dimension FEM in weak magnetic fields is a reliable way to determine T_C magnetic materials.-obtained by different methods, the values in FEM La1-xKxMnO3 differ significantly from each other, indicating a need for multifaceted evaluations of the effect to obtain reliable data.-that optimally doped samples value MEE reaches values comparable with the data for gadolinium and the maximum effect was observed near room temperature, which makes their alternative materials for magnetic refrigeration technology.JETP 139, 529-538 (2011), Physica B 406, 885-889 (2011). 6. The influence of grain size on magnetic and magnitokaloričeskie properties of ceramic samples manganita La 0.5 Ca 0.5 MnO3. The temperature dependence of the magnitokaloričeskogo effect of the anomalies detected evidence of coexistence of ferromagnetic metal and antiferromagnitnoj charge-ordered phases below TC. It is shown that the decrease in grain size up to 90 nm leads to the complete suppression of the antiferromagnitnoj charge-ordered phase.Journal of Applied Physics 113, 123,904 (2013).7. Together with colleagues from the Chelyabinsk State University theoretically and experimentally investigated magnitokaloričeskij effect in alloys Geissler Ni-Mn-X (X = Ga, In). Comparison of calculated by Monte Carlo FEA values with experimental values obtained by direct measurements. Received satisfactory agreement calculated and measured values of the FINITE ELEMENT METHOD in these alloys.Journal of Physics d: Applied Physics 44, 064012 (2011).8. tape the samples of the alloy Geissler Ni 31.3 Mn 36.5 Sn 13.2 in the field of magnitostrukturnogo phase transition found strong correlation MEE from time-with the passage of time the magnitude of the effect decreases towards zero in the limit. If you find that your MEE and other materials in the field of navigation magnetostructural also depends on the time, quest for the optimal materials for solid-state magnetic refrigerators will need to engage in a completely different direction.9. direct measurements carried out magnitokaloričeskogo effect microwires alloys Geissler coated with glass. After annealing microwire show ferromagnetic properties at room temperatures. The maximum value of the effect reaches ΔT = 0.22 K with magnetic field change ΔH = 18 koe. Demonstrated ability to manufacture magnetokaloričeskih materials for magnetic cooling in the form of glass-coated microwires. In terms of the practical application of such materials

Результаты (английский) 2:

1. The proposed and tested a precision method of measuring the magnetocaloric effect (MCE), based on the measurement of the oscillation amplitude of the sample temperature in an alternating magnetic field. Building on this basis, fully automated experimental setup for measuring the FEM has no analogues in the world and has a number of significant advantages inaccessible to other methods:
- High accuracy (ΔT ~ 0.001 K) measurements of the MCE, allowing to carry out research in weak magnetic fields. This means that this method can also be used for the diagnosis of the phase composition of ferro-antiferromagnetic.
- Opportunity studies of small samples (microwires, tape)
- small energy and time costs.
- The possibility of investigating the frequency dependence of the MCE,
first direct measurements of the MCE in tape samples alloys Heusler Ni50Mn40In10 and Ni50Mn37Sn13, promising for use in magnetic refrigeration technology. In the studied compositions found direct and inverse magnetocaloric effects associated with magnetic (paramagnetic - ferromagnetic, Ferry - antiferromagnetic) and structural (austenite - martensite) phase transitions.
Applied Physics Letters 97, 212505 (2010), JETP Letters 90, 736-739 (2009). 2. In the alloy Fe48Rh52 found a record value of the magnetocaloric effect (ΔT = 20 K in an alternating magnetic field amplitude ΔB = 8 T and a frequency of 0.13 Hz). It is shown that this material 3. A method for increasing the cooling efficiency of existing magnetocaloric materials by making a sandwich of two or more materials with similar magnetocaloric properties. The method was tested on manganites La0.7Ca0.3MnO3 (O16) and La0.7Ca0.3MnO3 (O18). Direct and indirect measurements of the magnetocaloric effect has been shown that in comparison with the starting materials, the cooling efficiency of the sandwich La0.7Ca0.3MnO3 (O16) + La0.7Ca0.3MnO3 (O18) increases by approximately 20%. Applied Physics Letters 101, 172401 (2012 ) 4. Investigation of thermal properties of cation-ordered manganite NdBaMn2O6 PrBaMn2O6 and found that: - the behavior of the magnetocaloric effect in NdBaMn2O6 in the phase transition in this composition is anomalous. In weak magnetic fields (up to 200 Oe) near the phase transition observed magnetostructural both direct and inverse magnetocaloric effect. In a magnetic field of 11 kOe forward and reverse effects are observed only in the cooling mode, while in the heating mode, the direct effect is not observed. This behavior is due to the freezing of the main FEM antiferromagnetic state at intermediate fields. Solid State Communications 151, 1820-1823 (2011). 5. Research magnetocaloric effect in manganites La1-xKxMnO3 three independent methods - the method of modulation of the magnetic field, by analyzing data on the specific heat in a magnetic field and without it, and the classical direct method showed that - the magnetic-field dependence of the MCE in weak magnetic fields, strictly follows the predictions of mean-field theory at account of the specific heat of the magnetic field and the accurate measurement of the FEM in weak magnetic fields is a reliable way to determine T_C magnetic materials. - obtained by different methods the value FEM La1-xKxMnO3 differ significantly from each other, indicating a need for diverse evaluations effect to obtain reliable data . - that optimally doped samples the value of MCE reaches values ​​comparable with the data for gadolinium, and the maximum effect is observed near room temperature, which makes them alternative materials for magnetic refrigeration technology. Zh 139, 529-538 (2011), Physica B 406, 885-889 (2011). 6. The influence of grain size on magnetic and magnetocaloric properties of ceramic samples of manganite La0.5Ca0.5MnO3. The temperature dependence of the magnetocaloric effect found anomalies suggesting the coexistence of ferromagnetic and antiferromagnetic metal charge-ordered phase below TC. It has been shown that a decrease in the grain size up to 90 nm leads to a complete suppression of the antiferromagnetic charge-ordered phase. Journal of Applied Physics 113, 123904 (2013). 7. Together with colleagues from the Chelyabinsk State University studied theoretically and experimentally the magnetocaloric effect in Heusler alloys Ni-Mn-X (X = Ga, In). A comparison is calculated using the Monte Carlo FEM values ​​with the experimental values ​​obtained by direct measurement. A satisfactory agreement between the calculated and measured values ​​of the MCE in these alloys. Journal of Physics D: Applied Physics 44, 064012 (2011). 8. The tape samples Heusler alloy Ni50.3Mn36.5Sn13.2 in magnetostructural phase transition revealed a strong dependence of the finite element method from time to time - over time the magnitude of the effect is reduced in the limit approaching zero. If you find that the finite element method and other materials in magnetostructural transitions also depend on the time, the search for optimal materials for solid-state magnetic refrigerators will need to be conducted in a completely different direction. 9. Direct measurements of magnetocaloric effect microwires Heusler alloys coated glass. After annealing microwires exhibit ferromagnetic properties at room temperature. The maximum magnitude of the effect reaches ΔT = 0.22 K with the magnetic field ΔH = 18 kOe. The possibility of production of magnetocaloric materials for magnetic refrigeration in the form of microwires coated glass. In terms of practical applications, such materials m

Результаты (английский) 3:

1. proposed and tested a precise method of measuring the магнитокалорического effect (sce), based on the measured amplitude осцилляций temperature model in the variable magnetic field.established on the basis of fully automated experimental setup for the measurement of fea is unique in the world and has several significant advantages unavailable to other methods:
high accuracy (ΔT ~ 0.001 k) measure the fea to conduct research in weak magnetic fields. this meansthis method can also be used for the detection of the phase composition of the ferro - антиферромагнетиков.
- to study small samples (микропровода, tape).small energy and time cost.
- to study frequency dependent fea;
first carried out direct measurements of fea in band samples of alloys гейслера Ni50Mn40In10 and Ni50Mn37Sn13,prospective for application in magnetic refrigeration technology. in the examined combinations of detected direct and reverse магнитокалорический effects associated with magnetic (парамагнетик is ферромагнетик,ferry is антиферромагнетик) and structural (austenite, martensite) фазовыми passages. applied physics letters, 97, 212505 (2010), writing in the жэтф 90, 736 739 (2009).

2.fusion of Fe48Rh52 discovered a record of магнитокалорического effect (ΔT = 20 k in the variable magnetic field amplitude and frequency ΔB = 8 тл 0.13 hz). it is shown that this material

3.the method of increasing the cooling efficiency of the existing магнитокалорических materials through the production of a sandwich of two or more materials with close магнитокалорическими properties.the method was tested on манганитах La0.7Ca0.3MnO3 (O16) and La0.7Ca0.3MnO3 (O18). the direct and indirect measurements магнитокалорического effect showed that compared with the original materialthe cooling efficiency of a La0.7Ca0.3MnO3 (O16) La0.7Ca0.3MnO3 (O18) increases by about 20%. "applied physics letters 101, 172401 (2012)

4. study теплофизических properties катион - orderly манганитов NdBaMn2O6 and PrBaMn2O6 showed that:.behavior магнитокалорического effect in NdBaMn2O6 on phase transition in this composition is anomalous in nature.in the field of weak magnetic fields (up to 200 um) in the vicinity of магнитоструктурного phase transition, there are both direct and reverse магнитокалорические effects.in a magnetic field 11 ke direct and reverse effects are observed only in the cooling mode, while in the heating mode of direct effect has not been observed.this behavior is due to the freezing of the main fea антиферромагнитного state of intermediate fields.
solid state communications 151, 1820–1823 (2011).

5.research магнитокалорического effect in манганитах La1 - xKxMnO3 three independent methods - method of modulating magnetic fieldthrough the analysis on heat in a magnetic field and without it and the classic direct method showed that.- магнитополевая dependence of fea in weak magnetic fields strictly follows the predictions of the theory of average field taking into account the dependence of specific heat of magnetic fieldand the accurate measurement of fea in weak magnetic fields is a reliable way to identify t _ c magnetic materials.
- derived by different methods of fea in La1 - xKxMnO3 differ significantly from each other.that points to the need for extensive evaluation of effect for obtaining reliable data.
- best допированных samples the fea reaches values comparable with data for gadolinium.and the maximum effect is observed near the room temperature, which makes them alternative materials for magnetic refrigeration technology. жэтф 139, 529 - 538 (2011), Physica b 406, 885 889 (2011).

6.the influence of grain size on the magnetic properties and магнитокалорические ceramic samples манганита La0.5Ca0.5MnO3. the temperature dependence of магнитокалорического effect detected anomalies.evidence of a ферромагнитной metal and антиферромагнитной зарядово - orderly phases below tc. showsthat the reduction of grain size of 90 nm resulted in total suppression of антиферромагнитной зарядово - orderly phase. "journal of applied physics, 113, 123904 (2013).

7.together with colleagues from the chelyabinsk state university is theoretically and experimentally analyzed магнитокалорический effect in alloys гейслера ni - mn - x (x = ga, in).compared with the method of monte carlo fea values with experimental values obtained by direct measurement.obtained satisfactory agreement of calculated and measured values of sce in these alloys. "the journal of physics d: applied physics, 44, 064012 (2011).

8. the band гейслера Ni50.3Mn36.5Sn13 alloy samples.2 in the area of магнитоструктурного phase transition was found a strong dependence of fea from time to time, with the passage of time, the effect is reduced to zero in the limit. if there is,the fea and other materials in the field of магнитоструктурных transitions also depends on the timesearch for optimal materials for solid-state magnetic refrigerators will need to be in a completely different direction.

9. carried out direct measurements of магнитокалорического effect микропроводов alloys гейслера,coated with glass. after annealing микропровода are ферромагнитные properties at room temperature. the maximum effect is ΔT = 0.22 k to change the magnetic field ΔH = 18 ke.demonstrated ability to manufacture магнетокалорических materials for magnetic refrigeration in the form of микропроводов covered with glass. from the point of view of practical application of such materials m