Magnetic studies of monoclinic Cu4O(SeO3)3, a copper-oxo-selenite derivative

José F Malta,António P Gonçalves,José A Paixão,Marta S.C Henriques,B.G Almeida,J Agostinho Moreira

doi:10.1051/epjconf/202023301002

José F Malta, António P Gonçalves + Show 4 more

Open Access

https://doi.org/10.1051/epjconf/202023301002

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Abstract

Cu4O(SeO3)3 is a copper-oxo-selenite belonging to the CuxO(SeO3)(x–1) family of the topological chiral magnet Cu2OSeO3. We report magnetometry and specific heat data measured in a monoclinic Cu4O(SeO3)3 single crystal grown through a Chemical Vapour Transport (CVT) reaction. Our study shows a typical antiferromagnetic behaviour, with a Néel temperature TN = 58 K, similar to that of the Cu2OSeO3 and an additional transition at 13 K. The effective magnetic moment per Cu atom is 1.84 μB, close to the expected theoretical value for Cu2+. The low-temperature M(H) curves, show a transition starting at Hc1 ~ 400 Oe at 1.8 K shifting to a lower value of ~ 280 Oe at 30 K, likely from a helical into a conical intermediate phase, and a second transition at Hc2 ~ 1 kOe, above which the net moment increases linearly with applied field. The magnetisation moment value in a 90 kOe field is 0.053 μB/Cu at 1.8 K and attains a maximum value of 0.061 μB at 13 K. Low-temperature specific heat measurements confirm the presence of the magnetic transition at 13 K, slightly shifting to lower temperatures under an applied magnetic field.

Highlights

Cu4O(SeO3)3 is copper-oxo-selenite derivative belonging to the family of CuxO(SeO3)(x–1), 4 ≤ x ≤ 2 compounds that includes the topological chiral magnet Cu2OSeO3, a most celebrated compound where a skyrmionic magnetic phase was found [1]
Magnetic studies deserve to be performed to better understand the nature of the magnetic interactions in a compound closely related to the topological chiral magnet Cu2OSeO3
The diffractogram confirmed the presence of Cu2OSeO3 as a majority phase (90% w/w), unreacted CuO (10% w/w) and no further extraneous phases. This powder was used for the Chemical Vapour Transport (CVT) reaction where single crystals were grown

Summary

Introduction

Cu4O(SeO3) is copper-oxo-selenite derivative belonging to the family of CuxO(SeO3)(x–1), 4 ≤ x ≤ 2 compounds that includes the topological chiral magnet Cu2OSeO3, a most celebrated compound where a skyrmionic magnetic phase was found [1]. Cu2OSeO3 crystallises in the chiral space group P213, the same as B20 compounds where skyrmions where first observed [2]. In the magnetic ground state of Cu2OSeO3, the Cu moments order in a long period (∼ 65 nm) helical structure (TN = 58 K), but close to TN and under a small applied magnetic field a new magnetic phase with a skyrmionic magnetic arrangement of the spins was found [1, 4].

Materials and Methods

K 10 K 20 K 30 K

Findings

Conclusions