Small-moment antiferromagnetic ordering in single-crystalline La₂Ni₇

Journal Article · Tue Jan 11 00:00:00 EST 2022 · Physical Review B

DOI:https://doi.org/10.1103/physrevb.105.014412· OSTI ID:1842216

Ribeiro, R. A. ^[1]; Bud'ko, S. L. ^[1]; Xiang, L. ^[1]; Ryan, D. H. ^[2]; Canfield, P. C. ^[1]

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1. Ames Lab., and Iowa State Univ., Ames, IA (United States)
2. Ames Lab., and Iowa State Univ., Ames, IA (United States); McGill Univ., Montreal, QC (Canada)

Single crystals of La₂Ni₇ have been grown out of a binary, La-Ni melt. Temperature dependent, zero magnetic field, specific heat, electrical resistivity, and low field magnetization measurements indicate that there is a series of antiferromagnetic phase transitions at T₁ = 61.0 ± 0.2 K, T₂ = 56.5 ± 0.2 K and T₃ = 42.2 ± 0.2 K. The three specific heat anomalies found at these temperatures qualitatively have very small entropy changes associated with them and the anisotropic M(H) data saturate at ~ 0.12 μ_B/Ni; both observations strongly suggesting the AFM order is associated with very small, itinerant, moments. Anisotropic, H_||c and H_⟂c, ρ(H) and M(H) isotherms as well as constant field, ρ(T) and M(T) sweeps manifest signatures of multiple phase lines and result in HT phase diagrams that are clearly anisotropic. Analysis of M(T) and M(H) data allow for the identification of the two lower temperature magnetically ordered states as antiferromagnetically ordered, with the moments aligned along the crystallographic c-axis, and the higher temperature, T₂ < T < T₁, state as having a finite ferromagnetic component. In addition, the metamagnetic transition at low temperatures, for H applied along the crystallographic c-axis (H_||c) appears to be a near classic example of a spin-flop transition, resulting in a field stabilized antiferromagnetic state with the moments ordered perpendicular to the c-axis. Finally, although the small moment ordering, and existence of multiple phase transitions in field and temperature, suggesting an energetic proximity of these states, could foretell a degree of pressure sensitivity, our measurements of R(T) for applied pressures up to 2.0 GPa indicate that there is very little pressure dependence of T₁, T₂ and T₃.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: Gordon and Betty Moore Foundation; USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 1842216
• Report Number(s): IS-J--10,698; DE-AC02-07CH11358; DE-AC02-07CH11358; GBMF4411
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 1 Vol. 105; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
anisotropic magnetoresistance
antiferromagnetism
magnetic anisotropy
magnetic phase transitions
magnetic susceptibility