THE INFLUENCE OF MAGNETIC ANISOTROPY ON THE MAGNETOCALORIC EFFECT IN Er_2Fe_(14)B SINGLE CRYSTAL NEAR SPIN-REORIENTATION TRANSITION AND CURIE TEMPERATURE

摘要

The adiabatic temperature change △T_(ad) was measured in an Er_2Fe_(14)B single crystal by a direct method in the temperature range of 100-650 K in a magnetic field up to μ_0H = 1.9 T applied along the crystallographic axes a and c. The application of 0.5 T field along the c-direction of the Er_2Fe_(14)B single crystal below spin reorientation temperature T_(SR)=325 K leads to a negative △T_(ad). The maximum △T_(ad) reaches -0.5 K in the temperature range of 310-320 K. Along the a-direction, the magnetocaloric effect above T_(SR) is positive and equals 0.5 K in magnetic field 0.5 T at temperatures of 330-350 K. At the Curie temperature (550 K) for a magnetic field change of 1.85 T, △T_(ad)= 1.34 K and 1.69 K along the crystallographic axes a and c, respectively.