ABSTRACT
This study aimed to obtain and investigate ZnCr2Se4 single crystals doped with rhenium. The single crystals were obtained by applying chemical vapour transport. An X-ray study confirmed the cubic (Fd3¯m) structure of the tested crystals. Thermal, magnetic, electrical, and specific heat measurements accurately determined the physicochemical characteristics, which revealed that the obtained single crystals are p-type semiconductors with antiferromagnetic order below the Néel temperature TN = 21.7 K. The Debye temperature had a value of 295 K. The substitution of Re-paramagnetic ions, possessing a screened 5d-shell, in place of Zn-diamagnetic ions, caused an increase in the activation energy, Fermi energy, and Fermi temperature compared to the pure ZnCr2Se4. The boost of the dc magnetic field induced a shift of TN towards lower temperatures and a spin fluctuation peak visible at Hdc = 40 and 50 kOe. The obtained single crystals are thermally stable up to 1100 °C.
ABSTRACT
In the present paper, the magnetization processes in amorphous alloys based on iron are discussed in detail. Our main goal was to measure the stabilization energy connected with the presence of microvoids (frozen during rapid cooling from the liquid phase) and to determine the interaction energy of relaxators with spontaneous magnetization vector (the so-called wN Neel) for amorphous Fe78Si13B9 alloys. A structural analysis of the alloys using X-ray measurements at the subsequent stages of crystallization was also performed.
ABSTRACT
Monocrystalline chalcogenide spinels ZnCr2Se4 are antiferromagnetic and semiconductor materials. They can be used to dope or alloy with related semiconducting spinels. Therefore, their Pb-doped display is expected to have unique properties and new potential applications. This paper presents the results of dc and ac magnetic measurements, including the critical fields visible on the magnetisation isotherms, electrical conductivity, and specific heat of the ZnCr2S4:Pb single crystals. These studies showed that substituting the diamagnetic Pb ion with a large ion radius for the Zn one leads to strong short-range ferromagnetic interactions in the entire temperature range and spin fluctuations in the paramagnetic region at Hdc = 50 kOe.
