Large magnetocaloric effect and magnetoresistance in ErNi single crystal

The magnetic properties,magnetocaloric effect and magnetoresistance in Er Ni single crystal have been investigated in detail.With decreasing temperature,Er Ni single crystal undergoes two successive magnetic transitions:a paramagnetic to ferromagnetic transition at T_(C)=11 K and a spin-reorientation transition at TS_(R)=5 K.Meanwhile,a sharp field-induced metamagnetic transition is observed below the T_(C)along the a axis.Er Ni single crystal possesses a giant magnetocaloric effect around T_(C).The maximum magnetic entropy change is-36.1 J(kg K)^(-1)along the a axis under the field change of 0-50 k Oe.In particular,the rotating magnetocaloric effect in Er Ni single crystal reaches its maximum under a relatively low field,and the maximum rotating entropy change with a value of 9.3 J(kg K)^(-1)is obtained by rotating the applied field from the[011]to[100]directions under 13 k Oe.These results suggest that Er Ni could be a promising candidate for magnetic refrigeration working at liquid-helium temperature region.Moreover,a complicated transport behavior is uncovered in Er Ni single crystal,which is attributed to the complex magnetic states and magnetic polaronic effect.Both positive and negative magnetoresistance are observed.A considerable large magnetoresistance with the value of-34.5%is acquired at 8 K under50 k Oe when the field is along the[100]direction.