J. Krok

TL;DR: The results of extensive studies of magnetic properties for the spinels were summarized in this article, where the authors showed quantitatively that the double exchange depending strongly on Cu concentration drives the transition from helimagnetism at $x=0$ through a conical structure to ferromagnetism, and the biquadratic exchange contribution was also included and proved to bring to close numerical agreement the theory and the experimental data.

TL;DR: In this article, temperature and field dependences of magnetization, paramagnetic susceptibility, magnetic anisotropy and neutron diffraction for CuxZn1-xCr2Se4 spinels are investigated.

TL;DR: The results of extensive studies of magnetic properties for the spinels Zn1−xGa 2x 3 Cr2Se4 are summarized in this paper, and it turns out that the magnetic properties of these spinels can be explained only if the existence of Cr ions in two valence states: Cr3+ and Cr2+, and the average ratio Ga:Cr2+ is about 1:1.

TL;DR: In this paper, a hypothesis on the magnetic structure of the four phases separated by the three phase transitions is put forward, and magnetization measurements were carried out using an induction method in strong, pulsed magnetic fields, in a temperature range of 2.8 K to 30 K.

TL;DR: In this paper, the magnetic properties of CuxZn1−xCr2Se4 are explained in terms of the molecular field approximation assuming the existence of 90° exchange interactions, and the exchange parameters and integrals for the whole series under consideration are calculated.