Optimized in situ crystal growth and disordered quasi-one-dimensional magnetism in ${\mathrm{Li}}_2{\mathrm{Mn}}_2({\mathrm{MoO}}_4{)}_3$

Journal Article · Mon Apr 13 04:00:00 EDT 2020 · Physical Review Materials

DOI:https://doi.org/10.1103/PhysRevMaterials.4.045404· OSTI ID:1616409

Franco, C. ^[1]; Wustrow, A. ^[2]; Xia, B. ^[3]; Baccarella, A. M. ^[3]; Burgos, F. ^[3]; Nicasio, J. ^[3]; Dooryhee, E. ^[4]; Neilson, J. R. ^[2]; Simonson, J. W. ^[3]

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1. Farmingdale State College, NY (United States); Stony Brook University
2. Colorado State Univ., Fort Collins, CO (United States)
3. Farmingdale State College, NY (United States)
4. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)

We present that the quasi-one-dimensional structure of ${\mathrm{Li}}_2{\mathrm{Mn}}_2{\left({\mathrm{MoO}}_4\right)}_3$ consists of three mutually distinct chains of ${\mathrm{Li}}_{1-x}{\mathrm{Mn}}_x$ -centered polyhedra in which Mn ostensibly adopts a $J=5/2{\mathrm{Mn}}^{2+}$ configuration. In situ x-ray scattering experiments carried out as crystallites emerge from a molten oxide solution facilitate the synthesis of large single crystals. Ex situ x-ray diffraction finds no evidence of long-range Li/Mn occupancy ordering, suggesting that the structure is effectively composed of finite chains of Mn moments of statistically varying lengths. UV/visible diffuse reflectance spectroscopy measurements establish a wide 3.43(12)-eV direct charge gap consistent with the local polyhedral coordination of the nominally ${\mathrm{Mn}}^{2+}$ species. The temperature $T$ dependence of the DC magnetic susceptibility $\chi$ reveals a fluctuating moment of only $2.74{\mu }_B\pm 0.01{\mu }_B$ /Mn, dramatically reduced from the $5.9{\mu }_B$ /Mn expected for ${\mathrm{Mn}}^{2+}$ . Meanwhile, the Weiss temperature ${\mathrm{\Theta }}_W=-89\pm 1$ K reveals antiferromagnetic fluctuations that are stymied from reaching an ordered state apparently by the chemical disorder intrinsic to the polyhedral chains. Measurements of magnetization vs field $H$ at $T\le 10$ K are far from saturation even at $H=5$ T and are strongly non-Brillouin-like, instead scaling as $H/T^{0.24\left(3\right)}$ and suggesting the presence of quantum fluctuations associated with an eventual quasi-one-dimensional, disordered magnetic phase.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). A Next Generation Synthesis Center (GENESIS); Stony Brook Univ., NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
• Grant/Contract Number: SC0019212; SC0012704
• OSTI ID: 1616409
• Alternate ID(s): OSTI ID: 2325564; OSTI ID: 1617681
• Journal Information: Physical Review Materials, Journal Name: Physical Review Materials Journal Issue: 4 Vol. 4; ISSN PRMHAR; ISSN 2475-9953
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

1-dimensional systems
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
Band gap
Crystal growth
Crystal structure
Crystal structures
DC susceptibility measurements
Magnetic insulators
Magnetism
X-ray diffraction