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Energy band structure and anomalies of the photoconductivity, electrical resistivity, and magnetoresistance of chalcogenide compounds Cd(1-x)GaxCr2Se4статья
- Авторы: Belov K.P., Koroleva L.I., Batorova C.D.
- Журнал: Soviet Journal of Experimental and Theoretical Physics
- Том: 43
- Номер: 1
- Год издания: 1976
- Первая страница: 74
- Последняя страница: 78
- Аннотация: An experimental study was made of the photoconductivity, electrical conductivity, magnetoresistance and photomagnetoresistance of Cd(1-x)GaxCr2Se4 single crystals (0<x<o.091). In the range x<0.01the photoconductivity in the ferromagnetic state was twobor three orders of magnitude higher than the dark coductivity. The temperature dependence of the photoresistivityhad a maximum in the region of the Curie point, whereas the dark resistivity ro_d had only a kink in the dependence ro_d(T). The photoresistivity was affected strongly by a magnetic field whereas this field did not influence ro_d.When the amount of gallium was increased, the photoconductivity disappeared rapidly and was not observed in compositions with x>0.019. The disappearance of photoconductivity was accompanied by a maximum of the dependence ro_d(T) and the resistivity was then affected strongly by a magnetic field.The anomalies observed in samples with low concentrations of gallium were attributed to the photogeneration of magnetic polarons, whereas the anomalies observed at high gallium concentration were explained by fluctuations of the magnetization due to fluctuations of the carrier density. Such carrier states were predicted in theoretical papers of Yanase, Kasuya, Krivoglaz, Nagaev and Grigin (1965-1972). Some hypotheses were made about the possible band structure of the investigated materials and about the nature of the photoferromagnetic effect observed by other workers in saples of the same compositions.
- Добавил в систему: Королёва Людмила Ивановна