Low-temperature specific heat of Nd2-xCexCuO single crystals (x=0 and 0.15) in applied magnet4ic-y fields

Abstract

Results are presented of low-temperature (0.3-6 K) specific-heat measurements on bulk single crystals of Nd2-xCexCuO4-y (x=0 and 0.15) in applied magnetic fields up to 8 T. The magnetic-field effect shows a highly anisotropic behavior : for both compounds only minor effects on the specific-heat curve have been found for fields applied parallel to the crystallographic c axis, whereas if the field is applied in the ab plane, a substantial broadening and shift of the zero-field maximum to higher temperatures is observed. A satisfactory quantitative description in terms of crystal-field and exchange interactions is given for the experimental data of the x=0 crystal. It is shown that application of the same description to the x=0.15 case is inadequate.