Proximate Quantum Spin Liquid on Designer Lattice

Liu, Xiaoran; Singh, Sobhit; Drouin-Touchette, Victor; Asaba, Tomoya; Brewer, Jess H.; Zhang, Qinghua; Cao, Yanwei; Pal, Banabir; Middey, S.; Kumar, P. S. Anil; Kareev, M.; Gu, Lin; Sarma, D. D.; Shafer, Padraic; Arenholz, Elke; Freeland, J. W.; Li, Lü; Vanderbilt, David; Chakhalian, Jak

doi:10.1021/acs.nanolett.0c04498

Cited by 5 publications

(2 citation statements)

References 81 publications

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“…With current thin-film deposition techniques, an exquisite control of the growth processes can be achieved, allowing the realization of crystalline oxide superlattices with an atomic control of the thickness [17][18][19]. Indeed, many impressive results have been achieved in perovskite superlattices systems, such as near room-temperature multiferroicity [20], the formation of ferroelectric vortices [21], the tuning of metal-insulator transitions [22], induced ferromagnetism [23], phases resembling quantum-spin liquids [24], and reversible structural transformations [25].…”

Section: Introductionmentioning

confidence: 99%

Effect of periodicity on the magnetic anisotropy in spinel oxide superlattices

Motti,

Riddiford,

Vaclavkova

et al. 2023

Phys. Rev. B

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Metamaterials, fabricated by assembling different compounds at the nanoscale, can have properties not found in naturally occurring materials, and therefore offer new avenues to develop novel devices. In the realm of spintronics, where the spin of the electrons is used to extend the capabilities of electronic devices, the quest for such new functional materials has expanded towards magnetic oxides. Here, finding methods to control their magnetic anisotropy is crucial to achieve higher memory density and longer stability. In order to address this challenge, we combined two oxides with a spinel crystal structure, synthesizing CoCr 2 O 4 /CoFe 2 O 4 superlattices with layers only few unit cells thick. We show that the superlattices present a reorientation of the magnetic easy axis from in plane to out of plane when warmed up, at a temperature determined by the periodicity. We can describe this with a model that includes the strain-induced anisotropy of the two materials and their different temperature dependence. This approach to create artificial materials, involving engineering superlattices to tailor the magnetic anisotropy, can be generalized to a wide range of compounds that can be grown strained on suitable substrates.

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Section: Introductionmentioning

confidence: 99%

Effect of periodicity on the magnetic anisotropy in spinel oxide superlattices

Motti,

Riddiford,

Vaclavkova

et al. 2023

Phys. Rev. B

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show abstract

“…However, the spins in the neighboring planes are ordered antiferromagnetically (AFM) with q = ( 1 2 , 1 2 , 1 2 ) to yield an overall AFM order in the absence of any external magnetic field below the Néel temperature T N = 20.4 K [15]. Due to such a peculiar magnetic behaviour, specially owing to the frustrated AFM ordering with q = ( 1 2 , 1 2 , 1 2 ), various exotic competing magnetic phases such as classical and quantum spin liquid phases, recently reported in (111)-oriented quasitwo-dimensional spinels through a geometric lattice design approach, can be realized in GCO at low temperatures [11,29,30].…”

Section: Introductionmentioning

confidence: 99%

Lattice dynamics and magnetic exchange interactions in GeCo2O4, a spinel with S = 1/2 pyrochlore lattice

Pramanik,

Singh,

Chowdhury

et al. 2020

Preprint

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Cobalt orthogermanate (GeCo2O4) is a unique system in the family of cobalt spinels ACo2O4 (A= Sn, Ti, Ru, Mn, Al, Zn, Fe, etc.) in which magnetic Co ions stabilize on the pyrochlore lattice exhibiting a large degree of orbital frustration. Due to the complexity of the low-temperature antiferromagnetic (AFM) ordering and long-range magnetic exchange interactions, the lattice dynamics and magnetic structure of GeCo2O4 spinel has remained puzzling. To address this issue, here we present theoretical and experimental investigations of the highly frustrated magnetic structure, and the infrared (IR) and Raman-active phonon modes in the spinel GeCo2O4, which exhibits an AFM ordering below the Néel temperature T N ∼21 K, followed by a cubic (F d 3m) to tetragonal (I41/amd) structural phase transition at T S ∼16 K. Our density-functional theory (DFT+U) calculations reveal that one needs to consider magnetic-exchange interactions up to the third nearest neighbors to get an accurate description of the low-temperature AFM order in GeCo2O4. At room temperature three distinct IR-active modes (T 1u) are observed at frequencies 680, 413, and 325 cm −1 along with four Raman-active modes A1g, T 2g(1), T 2g(2), and E g at frequencies 760, 647, 550, and 308 cm −1 , respectively, which match reasonably well with our DFT+U calculated values. All the IR-active and Raman-active phonon modes exhibit signatures of moderate spin-phonon coupling. The temperature dependence of various parameters, such as the shift, width, and intensity, of the Raman-active modes, is also discussed. Noticeable changes around T N and T S are observed in the Raman line parameters of the E g and T 2g modes, which are associated with the modulation of the Co-O bonds in CoO6 octahedra during the excitations of these modes.

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Proximate Quantum Spin Liquid on Designer Lattice

Cited by 5 publications

References 81 publications

Effect of periodicity on the magnetic anisotropy in spinel oxide superlattices

Effect of periodicity on the magnetic anisotropy in spinel oxide superlattices

Lattice dynamics and magnetic exchange interactions in GeCo2O4, a spinel with S = 1/2 pyrochlore lattice

Geometric control of emergent antiferromagnetic order in coupled artificial spin ices

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