P. Burgardt

Kondo scattering in a pure metal- beta cerium. II. Theoretical

For pt.I see ibid., vol.6, no.2, p.L49 (1976). A detailed explanation of the anomalous electrical resistivity of beta cerium is given.

Kondo scattering in a pure metal- beta cerium. I. Experimental

The electrical resistivity of DHCP beta Ce has been found to be anomalously large above 60K and to exhibit an order of magnitude drop below 20K. The magnetic susceptibility exhibits a Curie-Weiss behaviour above 40K, and magnetic ordering occurs at approximately 13K. The large resistivity is thought to be due to Kondo-like spin flip scattering which, at low temperatures, is quenched by the internal field associated with magnetic ordering.

Magnetic moments of ferromagnetic gadolinium alloys

Saturation magnetization and lattice parameter measurements have been made on samples of polycrystalline and single crystal c‐axis gadolinium and on samples of polycrystalline gadolinium alloyed with scandium, yttrium, lutetium, lanthanum, magnesium, ytterbium, and theorium. The magnetic measurements were made near 4.2 K in fields up to 30 kOe. Alloy concentrations ranged up to 30 atomic per cent. For pure single crystal gadolinium the saturation moment was measured to be 7.63±01μB per gadolinium atom. This result indicates the conduction electron contribution is about 13% higher than the value obtained from earlier measurements. For polycrystalline gadolinium the saturation moment per atom was found to be 7.555±.015μB. The excess moment per Gd atom for the polycrystalline alloys fell near a straight line when plotted as a function of the unit cell axes ratio c/a. The c/a ratios ranged from 1.583 to 1.595 and the excess moments were between 0.78 and 0.44μB. Surprisingly, there was no correlation of excess...

Magnetic critical temperature gap in Gd-Y alloys

Abstract In a search for Lifshitz points a very interesting and complex region in the magnetic phase diagram of Gd-Y alloys near 30 at% Y was found. An apparent jump (gap) in the highest ordering temperature and perplexing magnetic behavior was observed.

Electrical resistivity and magneto-resistance of very dilute Cu-Cr alloys

Abstract Measurements of the electrical resistivity from 1.5–80 K and the longitudinal magnetoresistivity from 0–95 kOe at 1.9, 4.2 and 25 K for every dilute Cr in Cu alloys are reported.

Magneto-resistivity of beta--cerium

Longitudinal magneto‐resistivity measurements of allotropically pure samples of dhcp cerium were made at temperatures from 4.2 to 90 K in fields up to 80 kOe. The results show negative magneto‐resistivity which is typical of field suppression of spin flip scattering. In the vicinity of the Neel temperature comples results were obtained which are interpreted as the interaction of internal fields with the applied field.

Low temperature magnetic and electrical properties of DHCP Ce-La alloys

Abstract Electrical resistivity and magnetic susceptibility measurements on CeLa alloys have shown that 5% La in βCe (dhcp) stabilizes βCe with respect to αCe, preventing β from transforming to α in the 15–50 K region. The remarkable Kondo-like properties of pure βCe are also found in the alloys over a wide concentration range.

Exchange vs Crystal Fields in Gd-Pr Single Crystal Alloys

We have measured the saturation magnetic moment of a hep single crystal of Gd0.91Pr0.09 and obtain a value of 6.63 Bohr magnetons per atom. If we assume a magnetic moment of 3.2 μ B per Pr atom and 7.55 μ B per Gd atom and normal spin exchange coupling so as to have antiparallel moments we obtain a theoretical value of 6.60 Bohr magnetons in excellent agreement with the observed value. This demonstrates that the exchange field dominates the hexagonal crystal field in this sample. The sample exhibited strong magnetic anisotropy which corroborates our interpretation of the results.