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Title: The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} studied by magnetization and hyperfine interactions measurements

Abstract

The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} was investigated by bulk magnetization measurements and measurements of hyperfine interactions using perturbed γ–γ angular correlation (PAC) spectroscopy. Magnetization measurements indicate the presence of four magnetic transitions associated with the Mn and Nd magnetic sublattices. At high temperatures, magnetic measurements show a change in the slope of the magnetization due to an antiferromagnetic transition around T{sub N} ∼ 425 K and a well defined ferromagnetic transition at T{sub C} ∼ 320 K. Moreover, at ∼210 K a peak is observed in the magnetization curve, which is assigned to the reorientation of the Mn spin, and at ∼25 K an increase in the magnetic moment is also observed, which is ascribed to the ordering of Nd ions. PAC measurements using {sup 140}La({sup 140}Ce) and {sup 111}In({sup 111}Cd) probe nuclei allowed the determination of the temperature dependence of the magnetic hyperfine field (B{sub hf}) at Nd and Mn sites, respectively. PAC results with {sup 111}Cd probe nuclei at Mn sites show that the dependence of B{sub hf} with temperature follows the expected behavior for the host magnetization associated with the magnetic ordering of Mn ions. From these results, the antiferromagnetic transition followed by a ferromagnetic ordering is clearly observed. PACmore » results with {sup 140}Ce probe nuclei at Nd sites, however, showed a strong deviation from the Brillouin function, which is attributed to the Ce 4f-electron contribution to B{sub hf}.« less

Authors:
; ; ;  [1];  [2]
  1. Instituto de Pesquisas Energéticas e Nucleares, Universidade de São Paulo, 05508-000 São Paulo (Brazil)
  2. Instituto de Física, Universidade de São Paulo, CP 66318, 05314-970 São Paulo (Brazil)
Publication Date:
OSTI Identifier:
22410144
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANTIFERROMAGNETIC MATERIALS; ANTIFERROMAGNETISM; CADMIUM 111; CERIUM 140; GAMMA SPECTROSCOPY; INDIUM 111; INTERMETALLIC COMPOUNDS; LANTHANUM 140; MAGNETIC MOMENTS; MAGNETIZATION; MANGANESE IONS; NEODYMIUM IONS; PERTURBED ANGULAR CORRELATION; SPIN; TEMPERATURE DEPENDENCE

Citation Formats

Bosch-Santos, B., E-mail: brianna@usp.br, Carbonari, A. W., Cabrera-Pasca, G. A., Saxena, R. N., and Freitas, R. S.. The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} studied by magnetization and hyperfine interactions measurements. United States: N. p., 2015. Web. doi:10.1063/1.4907330.
Bosch-Santos, B., E-mail: brianna@usp.br, Carbonari, A. W., Cabrera-Pasca, G. A., Saxena, R. N., & Freitas, R. S.. The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} studied by magnetization and hyperfine interactions measurements. United States. doi:10.1063/1.4907330.
Bosch-Santos, B., E-mail: brianna@usp.br, Carbonari, A. W., Cabrera-Pasca, G. A., Saxena, R. N., and Freitas, R. S.. Thu . "The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} studied by magnetization and hyperfine interactions measurements". United States. doi:10.1063/1.4907330.
@article{osti_22410144,
title = {The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} studied by magnetization and hyperfine interactions measurements},
author = {Bosch-Santos, B., E-mail: brianna@usp.br and Carbonari, A. W. and Cabrera-Pasca, G. A. and Saxena, R. N. and Freitas, R. S.},
abstractNote = {The magnetic behavior of the intermetallic compound NdMn{sub 2}Ge{sub 2} was investigated by bulk magnetization measurements and measurements of hyperfine interactions using perturbed γ–γ angular correlation (PAC) spectroscopy. Magnetization measurements indicate the presence of four magnetic transitions associated with the Mn and Nd magnetic sublattices. At high temperatures, magnetic measurements show a change in the slope of the magnetization due to an antiferromagnetic transition around T{sub N} ∼ 425 K and a well defined ferromagnetic transition at T{sub C} ∼ 320 K. Moreover, at ∼210 K a peak is observed in the magnetization curve, which is assigned to the reorientation of the Mn spin, and at ∼25 K an increase in the magnetic moment is also observed, which is ascribed to the ordering of Nd ions. PAC measurements using {sup 140}La({sup 140}Ce) and {sup 111}In({sup 111}Cd) probe nuclei allowed the determination of the temperature dependence of the magnetic hyperfine field (B{sub hf}) at Nd and Mn sites, respectively. PAC results with {sup 111}Cd probe nuclei at Mn sites show that the dependence of B{sub hf} with temperature follows the expected behavior for the host magnetization associated with the magnetic ordering of Mn ions. From these results, the antiferromagnetic transition followed by a ferromagnetic ordering is clearly observed. PAC results with {sup 140}Ce probe nuclei at Nd sites, however, showed a strong deviation from the Brillouin function, which is attributed to the Ce 4f-electron contribution to B{sub hf}.},
doi = {10.1063/1.4907330},
journal = {Journal of Applied Physics},
number = 17,
volume = 117,
place = {United States},
year = {Thu May 07 00:00:00 EDT 2015},
month = {Thu May 07 00:00:00 EDT 2015}
}
  • The magnetic behavior of Gd{sub 2}O{sub 3} nanoparticles, produced by thermal decomposition method and subsequently annealed at different temperatures, was investigated by magnetization measurements and, at an atomic level, by perturbed γ − γ angular correlation (PAC) spectroscopy measuring hyperfine interactions at {sup 111}In({sup 111}Cd) probe nuclei. Nanoparticle structure, size and shape were characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Magnetization measurements were carried out to characterize the paramagnetic behavior of the samples. XRD results show that all samples crystallize in the cubic-C form of the bixbyite structure with space group Ia3. TEM images showed that particlesmore » annealed at 873 K present particles with highly homogeneous sizes in the range from 5 nm to 10 nm and those annealed at 1273 K show particles with quite different sizes from 5 nm to 100 nm, with a wide size distribution. PAC and magnetization results show that samples annealed at 873 and 1273 K are paramagnetic. Magnetization measurements show no indication of blocking temperatures for all samples down to 2 K and the presence of antiferromagnetic correlations.« less
  • The temperature dependence of the magnetic hyperfine field (B{sub hf}) at Mn atom sites was measured in LaMn{sub 2}(Si{sub (1−x)}Ge{sub x}){sub 2}, with 0 ≤ x ≤ 1, compounds with perturbed γ−γ angular correlation spectroscopy using {sup 111}In({sup 111}Cd) as probe nuclei in the temperature range from 20 K to 480 K. The results show a transition from antiferromagnetic to ferromagnetic ordering for all studied compounds when Ge gradually replaces Si and allowed an accurate determination of the Néel temperature (T{sub N}) for each compound. It was observed that T{sub N} decreases when Ge concentration increases. Conversely, the Curie temperature increases with increase of Ge concentration.more » This remarkable change in the behavior of the transition temperatures is discussed in terms of the Mn-Mn distance and ascribed to a change in the exchange constant J{sub ex}.« less
  • The structure and magnetic properties of NdMn{sub 2}(Ge{sub 1{minus}x}Si{sub x}){sub 2} compounds (x=0{endash}1.0) have been investigated. All the compounds crystallize in ThCr{sub 2}Si{sub 2}-type structure. Substitution of Si for Ge leads to a linear decrease of the lattice constants and the unit-cell volume. With increasing temperature, for the compounds with x{le}0.5, both spin reorientation and ferromagnetic{endash} paramagnetic transition are observed as well at T{sub r} and T{sub C}(Mn), respectively. The spin reorientation temperature T{sub r} and the Curie temperature T{sub C}(Mn) decrease linearly with Si content from 215 and 339 K at x=0{endash}40 and 306 K at x=0.5, respectively. Inmore » compounds with 0.3{lt}x{le}0.5 the ferromagnetic component and the antiferromagnetic component may coexit. For compounds with x{ge}0.6 the ferromagnetic{endash}antiferromagnetic and the antiferromagnetic{endash}paramagnetic transition are observed and the Curie temperature T{sub C}(Nd) decreases monotonically while the N{acute e}el temperature T{sub N}(Mn) increases monotonically with Si content. A tendentious spin phase diagram has been obtained. The saturation magnetization at 1.5 K decreases first, goes through a minimum at x=0.5, and then increases again. {copyright} {ital 1997 American Institute of Physics.}« less