In:
The Journal of Chemical Physics, AIP Publishing, Vol. 61, No. 1 ( 1974-07-01), p. 282-291
Abstract:
The magnetic moment of a 2.44 cm diam spherical single crystal of gadolinium gallium garnet has been measured with stabilized fields of 500, 1000, 2500, 5000, 10 000, 15 000, 25 000, 40 000, 65 000, and 90 000 G along the [111] axis, over the range 0.35–4.2°K. The heat capacity was measured at the same fields and over the range 0.5–4.2°K, except that 500 G was omitted and zero field included. The magnetic moment reached saturation at 0.35°K and 90 000 G. Within the limit of error, a zero of entropy for the electronic and lattice systems was located at 90 000 G. By means of temperatures measured on 39 adiabatics, corrected with respect to entropy, which intersected the various isoerstedic heat capacity series, the entropies were evaluated as a function of field and temperature. The sample had an excess of electronic entropy of 0.5% over the maximum R ln8 for Gd3+ ion. Thus the sample must have contained 0.5% excess gadolinium over the stoichiometric amount for Gd3Ga5O12. Using the related correction factor 0.9950, the saturation value for Gd3Ga5O12 is found to be Msat[111] = 38 979 G · cm3/mole Gd3+, corresponding to a g[111] = 1.994±0.002. A correction of Msat[100] , taken from J. Chem Phys. 59, 4652 (1973), using the correction factor 0.9950, gives Msat[100] = 39 056 G · cm3/mole Gd3+, corresponding to g[100] = 1.998±0.002. Smoothed correlated values of the heat capacity, entropy, enthalpy, internal energy, magnetic moment and its differential isoerstedic temperature coefficient, differential isothermal magnetic susceptibility, and the isothermal work of magnetization have been tabulated over the ranges 0–90 kG and 0.5–4.2°K. The problem of location of the zero of entropy in a system where nuclear spin contributes to the heat capacity has been discussed.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
1974
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
Permalink
