High pressure synthesis and magnetic properties of cubic B20 MnGe and CoGe

A. V. Tsvyashchenko, V. A. Sidorov, L. N. Fomicheva, V. N. Krasnorussky, R. A. Sadykov, J. D. Thompson, K. Gofryk, F. Ronning, V. Yu Ivanov

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

20 Scopus citations

Abstract

Samples of MnGe and CoGe having cubic B20 structure were prepared at high pressure. Magnetic measurements showed that CoGe is a Pauli paramagnet, but MnGe exhibits antiferromagnetic-type ordering below TN = 175 K. The magnetic susceptibility of MnGe follows a Curie-Weiss law above 300 K with an effective magnetic moment μeff = 3.68 μB/f.u. and θp = + 231 K. The large positive value of θp indicates a strong ferromagnetic exchange. The value of the effective moment is close to the free Mn4+ ion (4F3/2) value 3.87 μB/f.u. From measurements of the magnetization of MnGe in fields up to 60 kOe and in the temperature range 2-350 K, we constructed its T-H magnetic phase diagram which is similar to that proposed for MnSi-type compounds with helical magnetic order. Specific heat measurements reveal that the total magnetic entropy of MnGe relative to nonmagnetic CoGe is equal to 3.55 J/mole-K (0.62Rln2).

Original languageEnglish
Title of host publicationMagnetism and Magnetic Materials V
PublisherTrans Tech Publications Ltd
Pages225-228
Number of pages4
ISBN (Print)9783037854365
DOIs
StatePublished - 2012
Event5th Moscow International Symposium on Magnetism, MISM 2011 - Moscow, Russian Federation
Duration: Aug 21 2011Aug 25 2011

Publication series

NameSolid State Phenomena
Volume190
ISSN (Print)1012-0394

Conference

Conference5th Moscow International Symposium on Magnetism, MISM 2011
Country/TerritoryRussian Federation
CityMoscow
Period08/21/1108/25/11

Keywords

  • B20 structure
  • CoGe
  • Helimagnet
  • High pressure synthesis
  • Magnetization
  • MnGe
  • Specific heat

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