STRUCTURAL, MAGNETIC, TRANSPORT, AND ELECTRONIC PROPERTIES OF RNi₄B AND RNi₄Al COMPOUNDS (R = RARE EARTH)

Abstract

We review the results of our studies on the R Ni 4X compounds, where X = B or Al and R = Y or rare earth. Additionally, many new data are provided in the case of R Ni 4 Al . However, the magnetic, structural, electronic, and transport properties are shown in order to highlight the tendencies and the behavior as a function of the f-occupancy rather than to present the detailed experimental data. We concentrate mainly on the mixed-valence and Kondo-like behavior in the CeNi 4X and the magnetic moments and phase transitions in the ferromagnetic representatives of the R Ni 4X compounds. A variety of the experimental techniques has been used in the investigations: magnetometry, neutron and X-ray diffractometry, X-ray photoemission spectroscopy as well as electrical resistivity and the specific heat measurements.

Neutron diffraction and magnetization measurements on CeNi4.2Mn0.8 and Y0.7Ni4.2Mn0.8

“…The hexagonal structure has been also confirmed in our previous studies on the CeNi 4.2 Mn 0.8 crystal [8]. This structure is of the CaCu 5 -type and is well known for a wide range of the RNi 4 M compounds (R = Y or rare earth; M = Al, Cu, Si, Ga) [9][10][11][12], derived from RNi 5 .…”

Valence Band and Core Levels of Ce5Ni2Si3Crystal Studied by X-ray Photoemission Spectroscopy

“…The G-S model shows how one can extract the values of the hybridization parameter ∆ between the f states and the conduction electrons, and the f occu- pancy n f based on the intensity ratios of the main peaks and the satellites. The details are provided elsewhere [4,8]. From the analysis we have got the estimated values ∆ = 4 meV and n f = 0.91.…”

Magnetocaloric effect in the ferromagnetic GdNi4M (M=Al, Si) and antiferromagnetic NdNiAl4 compounds

“…8 and included in Table 2. It provides similar values of the characteristic parameters as GdNi 4 Al and GdNi 4 Si but the ordering temperature is significantly reduced [10,11].…”

“…We have previously shown that both GdNi 4 Al and GdNi 4 Si exhibit similar ferromagnetic behaviour [10,12,13] with the ordering temperatures being in the range interesting for low temperature MCE applications. Figs.…”