Mar 20 – 23, 2023
Campus Garching
Europe/Berlin timezone

Magnetic excitations in the zigzag-chain compound KCu$_4$P$_3$O$_{12}$

Mar 20, 2023, 4:00 PM
Yards 4 - 6 (Fakultät für Maschinenwesen)

Yards 4 - 6

Fakultät für Maschinenwesen

Board: MO-147
Poster Magnetism, Superconductivity, Topological Systems, Magnetic Thin Films an other electronic phenomena Poster Session MONDAY


Masashi Matsuo (National Institute for Materials Science)


We report on the results of inelastic neutron scattering (INS) of KCu$_4$P$_3$O$_{12}$. Cu$^{2+}$ ions carry $S = 1/2$ spins. Four types of nearest-neighbor exchange interactions form the eight-spin zigzag-chain ($J_1 - J_2 - J_3 - J_4 - J_3 - J_2 - J_1$ chain). We evaluated the exchange interactions as $J_1 = -8.5$ meV (antiferromagnetic), $J_2 = -2.7$ meV, $J_3 = -3.9$ meV, and $J_4 = 6.2$ meV (ferromagnetic) from magnetic susceptibility and magnetization curves at several temperatures using a data-driven technique based on machine learning proposed by Tamura and Hukushima. In the eight-spin zigzag-chain with the values of the exchange interactions, the ground state (GS) is the spin-singlet state. The first-triplet, second-triplet, third-quintet, and fourth-triplet excited states (1ES, 2ES, 3ES, and 4ES, respectively) are located at 2.9, 4.2, 6.7, and 8.5 meV, respectively.
We performed INS experiments on KCu$_4$P$_3$O$_{12}$ powder using the HRC spectrometer at J-PARC (Proposal ID 2020B0026). We used incident neutrons with the energy 15.3 and 25.4 meV. Excitations at 5.5 K are most apparent at around $\omega =3$ meV and $Q = 0.7$ Å$^{-1}$. The 3 meV excitation exists in a wide $Q$ range, indicating cluster excitation, and corresponds to the excitation from GS to 1ES (2.9 meV). Excitations are seen up to about 6 meV, indicating the existence of the excitation from GS to 2ES (4.2 meV). We can see weak excitations around 9 meV, corresponding to the excitation from GS to 4ES (8.5 meV). Probably, we also observed the excitation from 1ES to 3ES (3.8 meV) at high-temperature data. As a result, the calculated energies of 1ES, 2ES, 3ES, and 4ES from GS are consistent with the experimental results. We will discuss the $Q$ dependence of the INS intensity.

Primary author

Masashi Matsuo (National Institute for Materials Science)


Prof. Koji Hukushima (The University of Tokyo) Dr Ryo Tamura (National Institute for Materials Science) Dr Shinichiro Asai (The University of Tokyo) Prof. Takatsugu Masuda (The University of Tokyo)

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