Magnetothermodynamics of Singlehyphen;Crystal CuSO4middot;5H2O. III. Properties over the Range of 0.4deg;ndash;4.2deg;K with Fields to 90 kG Verbar; to theggr;Magnetic Axis

摘要

The heat capacity and magnetic moment of CuSO4middot;5H2O have been measured over the range 0.4deg;ndash;4.2deg;K in stabilized magnetic fields of 0, 1, 3, 5, 10, 20, 30, 50, 70, and 90 kG. The field was directed along theggr;magnetic axis of a 3.70hyphen;cmhyphen;diam spherical single crystal. A sensitive carbon thermometer was used to measure the change of temperature during demagnetizations at essentially constant entropy to connect the several isoerstedic heathyphen;capacity series. Magnetic saturation, corrected for diamagnetism and an almost trivial temperaturehyphen;independent paramagnetism, was used to evaluate the gyromagnetic ratio asgggr;thinsp;equals;thinsp;2.269,and as a zero entropy reference. Within the limit of accuracy of the estimated ldquo;tailrdquo; above 4deg;K the electronic entropy was found to beRln2. All observations were uncorrected for the demagnetizing effect of the spherical sample. At 90 kG the heathyphen;capacity observations show that the nuclear spin polarization is in thermal equilibrium down to 0.7deg;K.