# Improvement of Large Anomalous Hall Effect in Polycrystalline Antiferromagnetic Mn3+xSn Thin Films

Tomoki Ikeda, Masakiyo Tsunoda, Mikihiko Oogane, Seungjun Oh, Tadashi Morita, Yasuo Ando

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

## Abstract

In order to improve the large anomalous Hall effect (AHE) in Mn3Sn thin films, we eliminated the co-existing Mn2Sn phase in the films by changing the composition; 50 nm thick polycrystalline Mn3+xSn thin films were fabricated on Si/SiO2 substrates by the sputtering method followed by a thermal annealing process in vacuum. The film compositions were Mn70Sn30(sample-A), Mn75Sn25(sample-B), and Mn80Sn20(sample-C) in as-deposited state and were slightly changed to be Mn75Sn25(sample-A), Mn77Sn23(sample-B), and Mn78Sn22(sample-C), respectively, after the annealing at 500 °C. From a structural analysis by X-ray diffractometry, the sample-C was considered to crystallize to Mn3Sn phase without passing the crystallization of Mn2Sn phase at 300 °C, differently from the sample-A. The saturation magnetization, $M-{\mathrm {S}}$, of the sample-A significantly increased below 250 K, corresponding with the Curie temperature of Mn2Sn. On the other hand, $M-{\mathrm {S}}$ did not show significant changes with cooling temperature in the samples-B and-C. An AHE was observed at the room temperature in all the samples. The anomalous Hall conductivity, $\sigma-{\mathrm {AH}}$, at the room temperature increased in magnitude, as the content of Mn increased. The sign of $\sigma-{\mathrm {AH}}$ changed from negative to positive in the sample-A with cooling temperature. On the other hand, the sign remained negative in the sample-C. These differences might be due to the elimination of co-existing Mn2Sn phase in the Mn3Sn thin films with enlarging the Mn content from the stoichiometry. Consequently, we successfully improved the large AHE in polycrystalline antiferromagnetic Mn3Sn thin films.

Original language English 8672635 IEEE Transactions on Magnetics 55 7 https://doi.org/10.1109/TMAG.2019.2899223 Published - 2019 Jul

## Keywords

• Anomalous Hall effect (AHE)
• Berry-phase
• antiferromagnetic materials
• kagome lattice

## ASJC Scopus subject areas

• Electronic, Optical and Magnetic Materials
• Electrical and Electronic Engineering

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