Magnetic properties of Gd-doped PbTe

1986 ◽  
Vol 64 (10) ◽  
pp. 1345-1347 ◽  
Author(s):  
F. T. Hedgcock ◽  
P. C. Sullivan ◽  
J. T. Grembowicz ◽  
M. Bartkowski

Electron paramagnetic resonance (EPR) and low-field ac susceptibility measurements were done on the rare-earth-doped semimagnetic semiconductor PbGdTe for the Gd composition range 100 ppm–10 at.%. For the lower concentrations, the EPR results indicate a fully resolved fine structure appropriate to the Gd3+ ion and g values close to the free-electron value. Susceptibility results show Curie–Weiss behaviour in all samples for temperatures above 10 K, small negative Curie temperatures, and Peff values corresponding to a Gd spin of 7/2. Deviations from this simple behaviour are observed for Gd concentrations greater than 5 at.% and for temperatures below 10 K. Evidence is observed for an antiferromagnetic clustering of impurity spins.

1987 ◽  
Vol 65 (8) ◽  
pp. 1023-1026 ◽  
Author(s):  
M. Bartkowski ◽  
D. J. Northcott ◽  
J. M. Park ◽  
A. H. Reddoch ◽  
D. F. Williams ◽  
...  

Measurements of electron paramagnetic resonance (EPR) and of susceptibility with a superconducting quantum interference device (SQUID) have been performed on Pb0.995Gd0.005Te crystals from 4.2 to 300 K. The EPR spectra consist of two components, one showing the fine structure of Gd3+ ions in a cubic environment and the other a broad line, which we attribute to clusters of interacting Gd ions. The resonant field of the cluster line is almost isotropic under sample rotation in the [Formula: see text] crystallographic plane, while the line width varies by a factor of 2.5 between [100] and 30° from it. This result suggests that an exchange-narrowing mechanism is responsible for the cluster line. The ratio of cluster-line intensity to fine-structure intensity increases with decreasing temperature down to 10 K and then decreases. This decrease may be related to the spin freeze-out seen in ac susceptibility. The line-width broadening of the cluster and the single-ion lines are similar below 20 K, with a higher rate for the cluster line. The Curie–Weiss temperature is negative and small for both clustered and single spins, reflecting a weak antiferromagnetic interaction.


Photonics ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 107
Author(s):  
Yuriy G. Galyametdinov ◽  
Dmitriy O. Sagdeev ◽  
Andrey A. Sukhanov ◽  
Violeta K. Voronkova ◽  
Radik R. Shamilov

Synthesis of nanoparticles doped with various ions can significantly expand their functionality. The conditions of synthesis exert significant influence on the distribution nature of doped ions and therefore the physicochemical properties of nanoparticles. In this paper, a correlation between the conditions of synthesis of manganese-containing cadmium sulfide or zinc sulfide nanoparticles and their optical and magnetic properties is analyzed. Electron paramagnetic resonance was used to study the distribution of manganese ions in nanoparticles and the intensity of interaction between them depending on the conditions of synthesis of nanoparticles, the concentration of manganese, and the type of initial semiconductor. The increase of manganese concentration is shown to result in the formation of smaller CdS-based nanoparticles. Luminescent properties of nanoparticles were studied. The 580 nm peak, which is typical for manganese ions, becomes more distinguished with the increase of their concentration and the time of synthesis.


2018 ◽  
Vol 20 (22) ◽  
pp. 15528-15534 ◽  
Author(s):  
P. Neugebauer ◽  
D. Bloos ◽  
R. Marx ◽  
P. Lutz ◽  
M. Kern ◽  
...  

Electron paramagnetic resonance (EPR) is a powerful technique to investigate the electronic and magnetic properties of a wide range of materials.


1980 ◽  
Vol 3 ◽  
Author(s):  
Sushil K. Misra ◽  
M. Jalochowski

ABSTRACTThe technique of electron paramagnetic resonance has been applied to study the magnetic properties of nickel acetate and nickel potassium tutton salt single crystals, using Mn2+ ion as probe. From the values of spin Hamiltonian parameters and linewidths at room, liquid nitrogen and liquid helium temperatures it is concluded that these crystals do not become magnetically ordered as the temperature is lowered to 3.2K, and thus the transition temperature, below which the crystal would order either ferromagnetically, or antiferromagnetically, for these crystals, should be below 3.2K.


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