Correlation between negative magnetoresistance effect and magnon excitations in single-crystalline CuCr1.6V0.4Se4

Ewa Malicka (1) , Tadeusz Groń (2) , Danuta Skrzypek (3) , Andrzej W. Pacyna (4) , Dariusz Badurski (5) , Alicja Waśkowska (5) , Sławomir Mazur (3) , Rafał Sitko (1)

1 Institute of Chemistry
2 Institute of Physics
3 Institute of Physics
4 The Henryk Niewodniczański Institute of Nuclear Physics
5 Institute of Low Temperature and Structure Research [Polish Academy of Sciences]

The structural, electrical and magnetic measurements as well as the electron spin resonance (ESR) spectra were used to characterize the single-crystalline CuCr1.6V0.4Se4 spinel and to study a correlation between negative magnetoresistance effect and magnon excitations. The ferromagnetic order below the Curie temperature TC = 193 K, a p-type semiconducting behavior, the ESR change from paramagnetic to ferromagnetic resonance at TC, a big value of ESR linewidth and its temperature dependence in paramagnetic region were established. The electrical studies revealed the negative magnetoresistance, which can be enhanced with increasing magnetic field and decreasing temperature while a detailed thermopower analysis showed the magnon excitations at low temperatures. The spin-phonon coupling is explained within a framework of the complex model of paramagnetic relaxation processes as the several-stage relaxation process in which the V3+ ions, the exchange subsystem and conduction electrons subsystem act as the intermediate reservoirs.

Mots clés: Physical Sciences

Ewa Malicka, Tadeusz Groń, Danuta Skrzypek, Andrzej W. Pacyna, Dariusz Badurski, et al.. Correlation between negative magnetoresistance effect and magnon excitations in single-crystalline CuCr1.6V0.4Se4. Philosophical Magazine, 2010, 90 (11), pp.1525-1541. ⟨10.1080/14786430903405504⟩. ⟨hal-00584287⟩