Магнитокалорический эффект в сплаве Fe-=SUB=-49-=/SUB=-Rh-=SUB=-51-=/SUB=- в импульсных магнитных полях до 50 T

The direct magnetocaloric effect (MCE) was measured in pulsed magnetic fields up to 50 T in the Fe49Rh51 alloy. At different initial temperatures in the metamagnetic phase transition with an increase in the field up to 20 T, a reverse MCE ∆T ≈ -8 K is observed, while a further increase in the field to 50 T results in a decrease in the absolute value of the adiabatic temperature change by ~ 1 K, which is connected with direct MCE and indicates a complete transition of the sample into the ferromagnetic phase. The maximum of the absolute value of the adiabatic temperature change |∆Т| = 9.8 K with a decrease in the magnetic field of 6 T on initial temperature of 310 K was observed.

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Simple Set-Up for Adiabatic Measurements of Magnetocaloric Effect

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.644.215 ◽

2015 ◽

Vol 644 ◽

pp. 215-218 ◽

Cited By ~ 7

Author(s):

P. Álvarez-Alonso ◽

J. López-García ◽

G. Daniel-Perez ◽

D. Salazar ◽

P. Lázpita ◽

...

Keyword(s):

Magnetic Field ◽

Magnetocaloric Effect ◽

Temperature Change ◽

Heusler Alloy ◽

Cost Effective ◽

Adiabatic Temperature ◽

Magnetic Phase Transitions ◽

Adiabatic Temperature Change ◽

Set Up ◽

The Magnetic Field

We present a cost-effective and robust set-up designed to measure directly the magnetic field-induced adiabatic temperature change. The system uses a piston to introduce/remove the sample to/from the magnetic field (μ0∆His up to 1.7T) created by an ordinary electromagnet. The temperature of the sample is controlled by a double pipe heat exchanger operating by the electrical heater and air flow circulation from a Dewar with liquid nitrogen to the sample holder assembly.We have measured the adiabatic temperature change, ΔTad, of two polycrystalline samples: Gd and Ni50Mn35In15Heusler alloy. At the second-order magnetic phase transitions (18oC for Gd and 42oC for Ni50Mn35In15), ΔTadunder μ0∆H=1.7T are 3.8±0.1oC for Gd and 1.9±0.1oC for Ni50Mn35In15. The Heusler alloy shows an inverse magnetocaloric effect: ΔTadis-1.5±0.1oC on cooling and-1.6±0.1oC on heating at the martensitic transformation temperatures of ~24oC and ~29oC, respectively.

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Tunable Magnetocaloric Properties of Gd-Based Alloys by Adding Tb and Doping Fe Elements

Materials ◽

10.3390/ma12182877 ◽

2019 ◽

Vol 12 (18) ◽

pp. 2877 ◽

Cited By ~ 1

Author(s):

Lingfeng Xu ◽

Chengyuan Qian ◽

Yongchang Ai ◽

Tong Su ◽

Xueling Hou

Keyword(s):

Magnetic Field ◽

Curie Temperature ◽

Temperature Change ◽

Indirect Measurement ◽

Adiabatic Temperature ◽

Doping Content ◽

Adiabatic Temperature Change ◽

Magnetocaloric Properties ◽

Capacity Calculation ◽

Low Magnetic Field

In this paper, the magnetocaloric properties of Gd1−xTbx alloys were studied and the optimum composition was determined to be Gd0.73Tb0.27. On the basis of Gd0.73Tb0.27, the influence of different Fe-doping content was discussed and the effect of heat treatment was also investigated. The adiabatic temperature change (ΔTad) obtained by the direct measurement method (under a low magnetic field of 1.2 T) and specific heat capacity calculation method (indirect measurement) was used to characterize the magnetocaloric properties of Gd1−xTbx (x = 0~0.4) and (Gd0.73Tb0.27)1−yFey (y = 0~0.15), and the isothermal magnetic entropy (ΔSM) was also used as a reference parameter for evaluating the magnetocaloric properties of samples together with ΔTad. In Gd1−xTbx alloys, the Curie temperature (Tc) decreased from 293 K (x = 0) to 257 K (x = 0.4) with increasing Tb content, and the Gd0.73Tb0.27 alloy obtained the best adiabatic temperature change, which was ~3.5 K in a magnetic field up to 1.2 T (Tc = 276 K). When the doping content of Fe increased from y = 0 to y = 0.15, the Tc of (Gd0.73Tb0.27)1−yFey (y = 0~0.15) alloys increased significantly from 276 K (y = 0) to 281 K (y = 0.15), and a good magnetocaloric effect was maintained. The annealing of alloys (Gd0.73Tb0.27)1−yFey (y = 0~0.15) at 1073 K for 10 h resulted in an average increase of 0.3 K in the maximum adiabatic temperature change and a slight increase in Tc. This study is of great significance for the study of magnetic refrigeration materials with adjustable Curie temperature in a low magnetic field.

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Adiabatic Temperature Change in Metamagnetic Ni(Co)-Mn-Al Heusler Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.738-739.446 ◽

2013 ◽

Vol 738-739 ◽

pp. 446-450 ◽

Cited By ~ 7

Author(s):

Vladimir Khovaylo ◽

Maria Lyange ◽

Konstantin Skokov ◽

Oliver Gutfleisch ◽

Ratnamala Chatterjee ◽

...

Keyword(s):

Magnetic Field ◽

Experimental Study ◽

Shape Memory Alloy ◽

Temperature Change ◽

Heusler Alloys ◽

Alloy System ◽

Adiabatic Temperature ◽

Adiabatic Temperature Change ◽

Measurement Protocol ◽

Magnetocaloric Properties

Two representatives of Ni(Co)-Mn-Al metamagnetic shape memory alloy system, Ni45Co5Mn31Al19 and Ni35Co15Mn35Al15, have been studied with respect to their magnetocaloric properties. Experimental study of the magnetocaloric effect by a direct measurement of the adiabatic temperature change ΔTad revealed that in both the samples ΔTad depends on the measurement protocol as well as on the magnetic prehistory of the samples. For the applied magnetic field µ0H = 1.93 T, the largest adiabatic temperature change, |ΔTad| ~ 0.7 K, has been observed in the Ni35Co15Mn35Al15 sample at T = 464 K.

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VII. Experiments, by the method of Lorentz, for the further determination the absolute value of the British Association Unit of Resistance, with an appendix on the determination of the pitch of a standard tuning-fork

Philosophical Transactions of the Royal Society of London ◽

10.1098/rstl.1883.0007 ◽

1883 ◽

Vol 174 ◽

pp. 295-322 ◽

Cited By ~ 3

Keyword(s):

Magnetic Field ◽

Electromotive Force ◽

Tuning Fork ◽

Circular Disc ◽

Absolute Value ◽

Single Turn ◽

The Absolute ◽

The Magnetic Field ◽

Axis Passing

In this method, which was employed by Lorentz in 1873, a circular disc of metal is maintained in rotation at a uniform and known rate about an axis passing through its centre, and is placed in the magnetic field due to a battery current which circulates through a coaxal coil of many turns. The revolving disc is touched at its centre and circumference by two wires. If the circuit were simply closed through a galvanometer, the instrument would indicate the current due to the electromotive force of induction acting against the resistance of the circuit. The electromotive force corresponding to each revolution is the same as would be generated in a single turn of wire coincident with the circumference of the disc by the formation or cessation of the battery current. If this be called γ , and M be the coefficient of induction between the coil and the circumference, m the number of revolutions per second, the electromotive force is m M γ . In the actual arrangement, however, the circuit is not simply closed, but its terminals are connected with the extremities of a resistance R, traversed by the battery current, and the variable quantities are so adjusted that the electromotive force R γ exactly balances that of induction. When the galvanometer indicates no current, the following relation, independent, it will be observed, of the magnitude of the battery current, must be satisfied— R = m M; and from this, M being known from the data of construction, the absolute resistance R of the conductor is determined. One of the principal difficulties to be overcome arises from the smallness of the resistance R, necessary for a balance, even when m and M are both increased as far as possible. Lorentz employed three resistances, ranging from ·0008 to ·002 of a mercury unit, and he evaded the necessity of comparing these small resistances with ordinary standards by constructing them of actual columns of mercury. His result was accordingly obtained directly in terms of mercury, and was to the effect that 1 mercury unit = ·9337 x 10 9 C. G. S. differing nearly 1 per cent. from the value (·941) obtained by ourselves.

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Magnetic field dependence of the maximum adiabatic temperature change

Applied Physics Letters ◽

10.1063/1.3607279 ◽

2011 ◽

Vol 99 (1) ◽

pp. 012501 ◽

Cited By ~ 31

Author(s):

M. D. Kuz'min ◽

K. P. Skokov ◽

D. Yu. Karpenkov ◽

J. D. Moore ◽

M. Richter ◽

...

Keyword(s):

Magnetic Field ◽

Temperature Change ◽

Field Dependence ◽

Magnetic Field Dependence ◽

Adiabatic Temperature ◽

Adiabatic Temperature Change

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Large electrocaloric response with superior temperature stability in NaNbO3-based relaxor ferroelectrics benefiting from crossover region

Journal of Materials Chemistry A ◽

10.1039/d0ta11423e ◽

2020 ◽

Author(s):

Ling Zhang ◽

Chunlin Zhao ◽

Ting Zheng ◽

Jiagang Wu

Keyword(s):

Temperature Change ◽

Temperature Stability ◽

Relaxor Ferroelectrics ◽

Adiabatic Temperature ◽

Next Generation ◽

Crossover Region ◽

Adiabatic Temperature Change

Electrocaloric refrigeration emerges as a newly-developing technology with potential to be the next generation of coolers. However, the combination of large adiabatic temperature change (ΔT) and good temperature stability remains...

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Large adiabatic temperature change in magnetoelastic transition in Ni50Mn35Cr2Sn13 Heusler alloy of granular nanostructure

10.1063/1.4946533 ◽

2016 ◽

Author(s):

H. R. Prakash ◽

S. K. Sharma ◽

S. Ram ◽

S. Chatterjee

Keyword(s):

Temperature Change ◽

Heusler Alloy ◽

Adiabatic Temperature ◽

Adiabatic Temperature Change

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Magnetocaloric Effect in Ni-Mn-Ga and Ni-Co-Mn-In Heusler Alloys

MRS Proceedings ◽

10.1557/proc-1200-g07-03 ◽

2009 ◽

Vol 1200 ◽

Cited By ~ 1

Author(s):

Vasiliy Buchelnikov ◽

Sergey Taskaev ◽

Mikhail Drobosyuk ◽

Vladimir Sokolovskiy ◽

Viktor Koledov ◽

...

Keyword(s):

Magnetic Field ◽

Magnetocaloric Effect ◽

Curie Point ◽

Direct Method ◽

Heusler Alloys ◽

Field Change ◽

Adiabatic Temperature Change ◽

Magnetic Field Change ◽

A Direct Method ◽

The Magnetic Field

AbstractThe positive magnetocaloric effect (MCE) in the vicinity of the Curie point in Ni2+xMn1-xGa (x=0.33, 0.36, 0.39) Heusler alloys and the negative and positive MCE near the metamagnetostructural (MMS) transition and the Curie point, respectively, in Ni45Co5Mn36.5In13.5 Heusler alloy has been measured by a direct method. For the magnetic field change ΔH = 2 T, the maximal adiabatic temperature change ΔTad at the Curie point in Ni2+xMn1-xGa alloys is larger than 0.6 K. For Ni45Co5Mn36.5In13.5 alloy, the maximal value of ΔTad = 1.68 K (for the same magnetic field change, ΔH = 2 T) is observed at the MMS phase transition temperature.

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