Er Substitution Research Articles

Defect chemistry of Er-doped BaTiO 3

Equilibrium electrical conductivity of Er-doped BaTiO 3 was studied in terms of Er substitution for Ba and/or Ti sites. When Er 3+ ion was substituted for the normal Ti site, the equilibrium conductivity showed a strong evidence of acceptor-doped behavior, while the Er replacement for the Ba site made the material semiconducting. In the case, excess Er was added to the stoichiometric BaTiO 3 up to 2.0 mol%, the conductivity profiles were similar to undoped BaTiO 3. However, the presence of Er greater than 3.0 mol% resulted in a gradual shift of the conductivity minimum toward low Po 2. This behavior is due to the acceptor type impurities, where Er acts as an effective acceptor. It was, thus, confirmed that the solubility of Er in the Ti site is greater than that in the Ba site.

Study of the Y 1− xEr xBa 2Cu 3O 7− δ system: electrical and fluctuation conductivity

The temperature dependence of in-plane electric resistance have been measured for a series of Y 1− x Er x Ba 2Cu 3O 6.94 single crystals with 0⩽ x⩽0.48. The data for different samples are identical suggesting that Er substitution for Y does not produce a sizable scattering of charge carriers and does not effect the fluctuation conductivity.

Magnetic and electronic properties of La 2− xSr xCuO 4 as studied by EPR of ER spin probes

In order to study the change in magnetic and electronic properties of the CuO 2 plane due to hole doping and the role of Er ion in the T c-suppression due to the rare earth substitution, Er 3+-EPR measurements have been performed on Er-doped La 2− x Sr x CuO 4 and YBa 2Cu 3O 7 compounds. It has been obtained that the EPR linewidth of Er 3+ spin in these compounds consists of residual linewidth and linewidths responsible for the Korringa and the Orbach relaxation processes. The change in the magnetic property of La 2− x Sr x CuO 4 due to hole doping has been studied by analysis of the residual linewidth. From analysis of the linewidths caused by the Korringa and the Orbach processes, the effect of Er substitution on the T c suppression in La 2− x Sr x CuO 4 is discussed in contrast to that in YBa 2Cu 3O 7 compound.

Influence of partial rare-earth substitution for Sm in the giant intrinsic magnetic hardness compound SmCo2Ni3

The phenomenon of giant intrinsic magnetic hardness is investigated in compounds R1−xSmxCo2Ni3 with R=Y, Pr, Gd, Tb, Er. Partial Er substitution for Sm actually increases magnetic hardness while all other substitutions decrease magnetic hardness. The strength of coercivity is thus dependent on both the sign and magnitude of the crystal field interaction. The temperature dependence of coercivity is complex in the case of Pr substitution as a result of competing effects from thermal activation and a decrease in anisotropy at low temperatures.