Pressure-Induced Colossal Magnetocaloric Effect in MnAs

Journal of Applied Physics

Суреш

Nigam

et al. 2008

Magnetic properties of isotropic Sm-Fe-N magnets produced by compression shearing method J. Appl. Phys. 111, 07A716 (2012) Stable vortex magnetite nanorings colloid: Micromagnetic simulation and experimental demonstration J. Appl. Phys. 111, 044303 (2012) Evidence for low temperature glassy behavior in La0.5Sr0.5CoO3 J. Appl. Phys. 111, 043902 (2012) Temperature dependent phonon Raman scattering of highly a-axis oriented CoFe2O4 inverse spinel ferromagnetic films grown by pulsed laser deposition Appl. Phys. Lett. 100, 071905 (2012) Additional information on J. Appl. Phys. The effect of Ge substitution for Si in SmMn 2 Si 2−x Ge x compounds has been studied. The Sm ordering temperature is found to be much larger in the compound with x = 2, as compared to the compounds with x = 0 and 1. The increase in the intralayer Mn-Mn distance is attributed to this variation. Among these three compounds, SmMn 2 Ge 2 is found to show reentrant ferromagnetism at low temperatures. The magnetic contribution to the heat capacity has been calculated in all the three compounds. The splitting of the ground state multiplet has been estimated by fitting the magnetic part of the heat capacity data, using the Schottky formula. The isothermal magnetic entropy change is found to remain the same for x = 0 and 1 but decreases in the compound with x = 2, though the nature of magnetic transition changes from second order to first order, as x is increased from 0 to 2. The electrical resistivity increases with Ge concentration. The excess resistivity in the antiferromagnetic region has been calculated.

Section: Introductionmentioning

confidence: 99%

Magnetic, magnetothermal, and magnetotransport properties in SmMn2Si2−xGex compounds

Journal of Applied Physics

Суреш

Nigam

et al. 2008

“…5,6 A few transition metal based compounds also show giant magnetocaloric effect, the representative examples being MnAs and LaFe 13 based systems, which undergo a first order ferromagnetic to paramagnetic transition at their ordering temperature. [7][8][9][10] Among the R-TM intermetallics, RMn 2 X 2 ͑X = Si, Ge͒ have attracted a lot of attention due to their interesting magnetic properties. [11][12][13][14] These compounds, in general, crystallize in the tetragonal ThCr 2 Si 2 -type structure.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ge substitution for Si on the anomalous magnetocaloric and magnetoresistance properties of GdMn2Si2 compounds

Journal of Applied Physics

Singh

Суреш

et al. 2007

The effect of distributed exchange parameters on magnetocaloric refrigeration capacity in amorphous and nanocomposite materials J. Appl. Phys. 111, 07A334 (2012) Particle size dependent hysteresis loss in La0.7Ce0.3Fe11.6Si1.4C0.2 firstorder systems Appl. Phys. Lett. 100, 072403 (2012) Magnetocaloric effect and refrigerant capacity in 0.44, 0.46 The effect of Ge substitution on the magnetization, heat capacity, magnetocaloric effect, and magnetoresistance of GdMn 2 Si 2−x Ge x ͑x = 0, 1, and 2͒ compounds has been studied. The magnetic transition associated with the Gd ordering is found to change from second order to first order on Ge substitution. Magnetic contributions to the total heat capacity and the entropy have been estimated. Magnetocaloric effect has been calculated in terms of adiabatic temperature change ͑⌬T ad ͒ as well as isothermal magnetic entropy change ͑⌬S M ͒ using the heat capacity data. The temperature dependence of the magnetocaloric effect in all the three compounds have shown broad peaks. The maximum values of ⌬S M and ⌬T ad for GdMn 2 Ge 2 are found to be 5.9 J / kg K and 1.2 K, respectively. The magnetoresistance is found to be very large and positive with a maximum value of about 22% in the case of GdMn 2 Ge 2 . In the other two compounds also, the magnetoresistance is predominantly positive, except in the vicinity of the Gd ordering temperature. The anomalous nature of the magnetocaloric effect and the magnetoresistance has been attributed to the canted magnetic structure of these compounds.

“…The concept of magnetic refrigeration, which is based on magnetocaloric effect (MCE), has attracted a great deal of attention from a large group of researchers and has triggered an intensive search for compounds with large MCE. [1][2][3][4] Giant magnetocaloric effect (GMCE) exhibited by many intermetallic compounds render them as potential refrigerants for magnetic refrigerators. [1][2][3][4] Large value of MCE spreads over a wide temperature range is considered as one of the most important requirements of a practical magnetic refrigerant system.…”

Section: -4mentioning

confidence: 99%

“…[1][2][3][4] Giant magnetocaloric effect (GMCE) exhibited by many intermetallic compounds render them as potential refrigerants for magnetic refrigerators. [1][2][3][4] Large value of MCE spreads over a wide temperature range is considered as one of the most important requirements of a practical magnetic refrigerant system. The compounds such as Gd 5 Si 2 Ge 2 , MnAs, LaFe 13−x Si x , MnFe(P 1−x As x ), RM 2 [R= rare-earth (Sm,Gd, Tb, Dy etc.)…”

Section: -4mentioning

confidence: 99%

Magnetocaloric effect and refrigeration cooling power in amorphous Gd7Ru3 alloys

2015

AIP Advances

In this paper, we report the magnetic, heat capacity and magneto-caloric effect (MCE) of amorphous Gd 7 Ru 3 compound. Both, temperature dependent magnetization and heat capacity data reveals that two transitions at 58 K and 34 K. MCE has been calculated in terms of isothermal entropy change (∆S M ) and adiabatic temperature change (∆T ad ) using the heat capacity data in different fields. The maximum values of ∆S M and ∆T ad are 21 Jmol −1