Magnetic phase transitions in erbium

Journal of Physics: Condensed Matter, 2002

Using a capacitive dilatometer we investigated the magnetoelastic behaviour of single-crystalline ErNi 2 B 2 C in the temperature range 1.8 K T 16 K and for external magnetic field in the tetragonal ab-plane µ 0 H 6 T. For T T N = 6.4 K the longitudinal magnetostriction coefficient is negative, whereas the transverse one is positive. The thermal evolution of the lattice distortion ε γ = (λ ⊥ − λ)/ √ 2 is in agreement with that of the previously reported spontaneous tetragonal-to-orthorhombic distortion determined by neutron diffraction. The behaviour is influenced by the distribution of the magnetic domains in the crystal. The H-T phase diagram, constructed from the magnetostriction curves, shows the well-known cascade of metamagnetic transitions between several phases (antiferromagnetic AF1, ferrimagnetic F1, F2) in the field range 0 < µ 0 H < 2.1 T below T N. On the basis of a Hamiltonian consisting of an exchange, a crystal-field, a Zeeman, and a magnetoelastic term, we were able to reproduce reasonably well the H-T phase diagram as well as various forced magnetostriction curves.

High Pressure Research, 2002

Electrical resistivity measurements performed on a single crystal of erbium as a function of temperature and hydrostatic pressure have provided a preliminary p-T phase diagram. The results have been interpreted in terms of a model for the magnetic structures of Er deduced from neutron diffraction studies at ambient pressure. This model predicted the existence of a magnetic structure with a wave vector of Q ¼ 2=7 c* at 4.2 K, when the applied pressure is larger than 3 kbar. This paper reports a neutron diffraction study of erbium made in the temperature range of 4 to 100 K, at pressures between 0.5 and 6 kbar. We have observed the predicted suppression of the low temperature conical ferromagnetic phase and the emergence of a new phase with Q ¼ 8=33 c*. The neutron diffraction measurements has enabled us to identify the various phases that develop from the cycloidal phases previously observed at atmospheric pressure.

Physical Review B, 2000

A comprehensive resistance study of erbium subjected to a hydrostatic pressure is presented. From the experimental results we derive a p-T phase diagram for the magnetic phases in erbium. In the zero-temperature limit, the conical structure is predicted to transform into the cycloidal one at a pressure of about 1.3 kbar. Experimentally, the transition is found to occur between 1 and 3 kbar at 4.5 K. The experimental results are analyzed in terms of a variational calculation of the resistivity using the model developed for erbium from previous experiments. The theory of Elliott and Wedgwood is utilized in the account of the superzone effects. The analysis indicates that the a-axis resistivity is slightly affected by the superzones. In the c-axis case the superzone effects do not simply scale with the magnetization, but also reflect the 20% change of the ordering wave vector. This occurs between T N and T C at ambient pressure, and at 4.5 K when the pressure is increased from 1 to 3 kbar. It is tentatively proposed that the tilted cycloidal structure exists in Er, just above T C at ambient pressure and in the interval between 1.3 and 9 kbar at zero temperature.

Acta Physica Polonica Series a

High precision measurements of magnetoresistance ∆ρ/ρ = f (T, H) and magnetization M (T, H) were carried out on single crystals of rare-earth dodecaboride ErB12 at temperatures in the interval 1.8-30 K in magnetic fields up to 70 kOe. The high accuracy of the experiments allowed us to perform numerical differentiation and analyze quantitatively the behavior of the derivative d(∆ρ/ρ)/dH = f (T, H) and of the magnetic susceptibility χ(T, H)= dM /dH in paramagnetic and magnetically ordered (antiferromagnetic, T N ≈ 6.7 K and T M ≈ 5.85 K) phases of ErB 12 . It was shown that negative magnetoresistance anomalies observed in present study in paramagnetic state of ErB 12 may be consistently interpreted in the framework of a simple relation between resistivity and magnetization -∆ρ/ρ ∼ M 2 .

International Journal of Research in Engineering and Technology, 2017

We report the synthesis of homogeneous single phase nanoparticles of ErCrO 4 and ErCrO 3 by a modified sol-gel hydrothermal method. Temperature dependent annealing results in the formation of ErCrO 4 and ErCrO 3 phases at low and high temperatures. Analysis of the X-ray diffractograms reveal that ErCrO 4 crystallizes into tetragonal structure with space group I41/amd and ErCrO 3 into orthorhombic structure with space group Pnma. Morphological analysis confirms uniformly distributed nanoparticles of ErCrO 4 with size 20 nm and ErCrO 3 with 70 nm. DC magnetic measurements show that ErCrO 4 undergoes a paramagnetic-antiferromagnetic transition at 16 K, the Néel temperature (T N) due to the superexchangeEr-O-Cr-O-Erantiferromagnetic interactions and that the Er 3+ ions alone carry a magnetic moment while Cr exists in Cr 5+ (3d 0) valence state. And ErCrO 3 undergoes paramagnetic-antiferromagnetic transition at 137 K (T N), due to Cr-O-Cr superexchange interaction, with canting of spins at Cr sites below Néel temperature, attributed to antisymmetric Dzyaloshinsky-Moriya (DM) exchange interaction between neighbouring spins.

Physica B: Condensed Matter, 1994

Phase diagram (H,T) investigation of a single crystal of erbium by direct measurement of dR/dT.

Dalton Transactions, 2015

The magnetic properties of two similar Er 3+ complexes have been investigated. [Er(tpm) 3 (bipy)] (Htpm = 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione and bipy = 2,2'-bipyridine) displays thermally activated slow relaxation of magnetisation under a zero direct-current (DC) field. Under an applied H DC field of 1000 G, [Er(tpm) 3 (bipy)] exhibits two thermally activated processes with energy barriers of 9 and 40 K, while [Er(tfa) 3 (bipy)] (Htfa = 4,4,4-trifluoro-1-(2-furyl)-1,3-butanedione) shows only one activated process with a barrier of 15 K. Both compounds are luminescent in the solid state, emitting in the near IR region. † Electronic supplementary information (ESI) available: Vibrational characterization (FTIR and Raman), 1 H-NMR and 13 C-NMR spectroscopic data, TG/DTG/ DTA analysis, UV-Vis absorption and UV-Vis-NIR diffuse reflectance spectra, emission spectrum in the visible region, excitation spectrum, ligand-associated PL decay and static magnetic measurements for the [Er(tfa) 3 (bipy)] complex. Additional AC susceptibility measurements for both [Er(tfa) 3 (bipy)] and [Er(tpm) 3 (bipy)] samples. CCDC 1010428 for [Er(tfa) 3 (bipy)]. For ESI and crystallographic data in CIF or other electronic format see

Journal of Magnetism and Magnetic Materials, 1986

Inorganic Chemistry, 2008

Single crystals of four erbium-chromium sulfides have been grown by chemical vapor transport using iodine as the transporting agent. Single-crystal X-ray diffraction reveals that in Er 3 CrS 6 octahedral sites are occupied exclusively by Cr 3+ cations, leading to one-dimensional CrS 4 5chains of edge-sharing octahedra, while in Er 2 CrS 4 , Er 3+ , and Cr 2+ cations occupy the available octahedral sites in an ordered manner. By contrast, in Er 6 Cr 2 S 11 and Er 4 CrS 7 , Er 3+ and Cr 2+ ions are disordered over the octahedral sites. In Er 2 CrS 4 , Er 6 Cr 2 S 11 , and Er 4 CrS 7 , the network of octahedra generates an anionic framework constructed from M 2 S 5 slabs of varying thickness, linked by one-dimensional octahedral chains. This suggests that these three phases belong to a series in which the anionic framework may be described by the general formula [M 2n+1 S 4n+3 ] x-, with charge balancing provided by Er 3+ cations located in sites of high-coordination number within one-dimensional channels defined by the framework. Er 4 CrS 7 , Er 6 Cr 2 S 11 , and Er 2 CrS 4 may thus be considered as the n ) 1, 2, and ∞ members of this series. While Er 4 CrS 7 is paramagnetic, successive magnetic transitions associated with ordering of the chromium and erbium sub-lattices are observed on cooling Er 3 CrS 6 (T C (Cr) ) 30 K; T C (Er) ) 11 K) and Er 2 CrS 4 (T N (Cr) ) 42 K, T N (Er) ) 10 K) whereas Er 6 Cr 2 S 11 exhibits ordering of the chromium sub-lattice only (T N ) 11.4 K).

Journal of Low Temperature Physics, 2010

The magnetic measurements have been performed for high fields up to 18 T and low temperatures down to 0.5 K on the single crystal compound ErCu 2 Si 2 . In the temperature dependence of magnetic susceptibility, two anomalies are seen at T N = 1.51 K and T t = 0.97 K which is corresponding to an antiferromagnetic ordering temperature and may come from a change of magnetic structure. Low temperature magnetization shows a metamagnetic transition around 0.4 T along the easy magnetization direction of [001]. The magnetization is almost saturated above 3 T and reaches 8.8μ B /f.u. at 18 T. A metamagnetic transition appears around 0.5 T in the basal plane magnetization processes as well. The anisotropy within the basal plane is fairly large for high fields. These behaviors have been explained from crystalline electric field effects and magnetic interaction in terms of molecular field.