Rotational Magnetocaloric Effect in the Er2Fe14B Single Crystal

The adiabatic temperature change ΔT
_ad
and the isothermal entropy change ΔS
_m
were measured in a Er
₂
Fe
₁₄
B single crystal in the temperature range of 250-370 K under a magnetic field change of Δμ
₀
H = 1.9 T. The magnetic field was applied along the crystallographic axes a and c. Under adiabatic conditions, the application of a 0.5 T field along the c-direction of the Er
₂
Fe
₁₄
B single crystal leads to a negative ΔT
_ad
at temperatures below the spin-reorientation temperature T
_SR
= 323 K. In this case, the maximum ΔT
_ad
reaches -0.9 K in the temperature range of 270-280 K. Along the a-direction, the magnetocaloric effect above T
_SR
is positive, and ΔT
_ad
reaches 0.68 K in the magnetic field 0.5 T at the temperatures of 320-330 K. Under isothermal conditions, the maximal magnetic entropy change is -0.86 J kg
^-1
K
^-1
at 328 K when the magnetic field is applied along the a-direction and ΔS
_m
= 1.27 J kg
^-1
K
^-1
at 275 K if the single crystal is magnetized along the c-axis.