μSR study of Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} and EuMn{sub 2}O{sub 5} multiferroics

Journal Article · Thu Dec 15 00:00:00 EST 2016 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776116130215· OSTI ID:22617111

Andrievskii, D. S.; Barsov, S. G.; Getalov, A. L. ^[1]; Golovenchits, E. I. ^[2]; Komarov, E. N.; Kotov, S. A. ^[1]; Mishchenko, A. Yu. ^[3]; Sanina, V. A. ^[2]; Shcherbakov, G. V. ^[1]

---

1. National Research Center Kurchatov Institute, Petersburg Nuclear Physics Institute (Russian Federation)
2. Russian Academy of Sciences, Ioffe Physical–Technical Institute, Institute (Russian Federation)
3. National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation)

A comparative μSR study of ceramic samples of the EuMn{sub 2}O{sub 5} and Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} multiferroics is performed in the temperature range from 15 to 300 K. It is found that the Ce doping of the EuMn{sub 2}O{sub 5} sample slightly reduces the temperature of the magnetic phase transition from T{sub N} = 45 K for the EuMn{sub 2}O{sub 5} sample to T{sub N} = 42.5 K for the Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} sample. Below the temperature T{sub N} for both samples, there are two types of localization of a thermalized muon with different temperature dependences of the precession frequency of the magnetic moment of the muon in an internal magnetic field. The higher frequency in both samples refers to the initial antiferromagnetic matrix. The behavior of this frequency in Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} follows the Curie–Weiss law with the exponent β = 0.29 ± 0.02, which differs from the value β = 0.39 standard for 3D Heisenberg magnetics and is observed in EuMn{sub 2}O{sub 5}, because of the strong frustration of the doped sample. The temperature-independent low frequency is due to the presence of Mn{sup 3+}–Mn{sup 4+} ferromagnetic pairs located along the b axis of the antiferromagnetic matrix and in the regions of phase separation, which contain such ion pairs and e{sub g} electrons recharging them. In both samples, polarization losses are the same (about 20%) and are associated with the formation of Mn{sup 4+}–Mn{sup 4+} + Mu complexes near Mn{sup 3+}–Mn{sup 4+} ferromagnetic pairs. In the temperature interval from 25 to 45 K, the separation of the Eu{sub 0.8}Ce{sub 0.2}Mn{sub 2}O{sub 5} structure into two fractions where the relaxation rates of polarization of muons differ by an order of magnitude is revealed. This effect is due to a change in the state of regions of phase separation (1D superlattices) at the indicated temperatures. Such effect in EuMn{sub 2}O{sub 5} is significantly weaker.

• OSTI ID: 22617111
• Journal Information: Journal of Experimental and Theoretical Physics, Vol. 123, Issue 6; Other Information: Copyright (c) 2016 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
CERAMICS
CERIUM ADDITIONS
CURIE-WEISS LAW
DOPED MATERIALS
EUROPIUM COMPOUNDS
ION PAIRS
LOSSES
MAGNETIC FIELDS
MAGNETIC MOMENTS
MANGANATES
MANGANESE IONS
MUON SPIN RELAXATION
NEEL TEMPERATURE
PHASE TRANSFORMATIONS
POLARIZATION
PRECESSION
RELAXATION
SUPERLATTICES
TEMPERATURE DEPENDENCE