Drastic enhancement of magnetic critical temperature and amorphization in topological magnet EuSn2P2 under pressure

Abstract

High pressure is an effective tool to induce exotic quantum phenomena in magnetic topological insulators by controlling the interplay of magnetic order and topological state. This work presents a comprehensive high-pressure study of the crystal structure and magnetic ground state up to 62 GPa in an intrinsic topological magnet EuSn2P2. With a combination of high resolution X-ray diffraction, 151Eu synchrotron Mössbauer spectroscopy, X-ray absorption spectroscopy, molecular orbital calculations, and electronic band structure calculations, it has been revealed that pressure drives EuSn2P2 from a rhombohedral crystal to an amorphous phase at 36 GPa accompanied by a fourfold enhancement of magnetic ordering temperature. In the pressure-induced amorphous phase, Eu ions take an intermediate valence state. The drastic enhancement of magnetic ordering temperature from 30 K at ambient pressure to 130 K at 41.2 GPa resulting from Ruderman–Kittel–Kasuya–Yosida (RKKY) interactions likely attributes to the stronger Eu–Sn interaction at high pressure. These rich results demonstrate that EuSn2P2 is an ideal platform to study the correlation of the enhanced RKKY interactions, disordered lattice, intermediate valence, and topological state.

Pressure Induced Amorphization of Pb2+ and Pb4+ in Perovskite PbFeO3

“…Interestingly, the glassy distribution of Pb 2+ /Pb 4+ in PbCrO 3 is absent in the Pb 2+ Cr 4+ O 3 HP phase, while PbFeO 3 exhibits pressure-induced amorphization of Pb 2+ /Pb 4+ . Such pressure-induced amorphization has been reported in a wide variety of systems such as AlPO 4 , , SnI 4 , VO 2 , EuIn 2 As 2 , and EuSn 2 P 2 and has been a growing area of interest. − …”

Strong enhancement of magnetic ordering temperature and structural/valence transitions in EuPd 3 S 4 under high pressure

“…Whereas such large values are rather uncommon for rare-earth compounds, similarly large values have been found for some Eu-based intermetallics, such as EnIn 2 As 2 ( 22 ), EuSn 2 As 2 ( 23 ), EuSn 2 P 2 . ( 24 ), and EuMnBi 2 ( 25 ).…”

Robust magnetism and crystal structure in Dirac semimetal EuMnBi2 under high pressure

“…Mössbauer spectroscopy under high-pressure sample environment is more feasible at the third-generation synchrotron sources compared to the conventional method using radioactive sources, due to the enhanced brilliance and compact size of the x-ray beams. Therefore, SMS is frequently employed in high-pressure magnetic research [28][29][30][31][32]. In conventional Mössbauer spectroscopy using a radioactive source, the Doppler effect modulates the source energy for energy-dependent absorption, whereas in time-domain SMS experiments, synchrotron radiation with an energy linewidth of ∼1 meV is used to coherently excite nuclear transitions and probe the hyperfine interactions from the reemitted radiation in time domain.…”