Fragile magnetic order in the honeycomb lattice Iridate<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi mathvariant="normal">Na</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">IrO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>revealed by magnetic impurity doping

Mehlawat, Kavita; Sharma, Gyaneshwar; Singh, Yogesh

doi:10.1103/physrevb.92.134412

Cited by 19 publications

(19 citation statements)

References 32 publications

(32 reference statements)

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“…f changing from 100 to 10000 Hz. This value is close to those observed in other insulating spin glasses [34][35][36][37][38]. The strong frequency dependence evidences a broad distribution of the spin relaxation times around T f , typical for a spin glass [34][35][36].…”

supporting

confidence: 88%

Spin-Glass Ground State in a Triangular-Lattice Compound YbZnGaO4

Ma¹,

Wang²,

Dong³

et al. 2018

Phys. Rev. Lett.

147

134

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We report on comprehensive results identifying the ground state of a triangular-lattice structured YbZnGaO_{4} as a spin glass, including no long-range magnetic order, prominent broad excitation continua, and the absence of magnetic thermal conductivity. More crucially, from the ultralow-temperature ac susceptibility measurements, we unambiguously observe frequency-dependent peaks around 0.1 K, indicating the spin-glass ground state. We suggest this conclusion holds also for its sister compound YbMgGaO_{4}, which is confirmed by the observation of spin freezing at low temperatures. We consider disorder and frustration to be the main driving force for the spin-glass phase.

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supporting

confidence: 88%

Spin-Glass Ground State in a Triangular-Lattice Compound YbZnGaO4

Ma¹,

Wang²,

Dong³

et al. 2018

Phys. Rev. Lett.

147

134

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“…A maximum is observed at 0.33 K which is too broad to indicate a phase transition to long-range magnetic order. This peak shifts by 0.015 K over the entire frequency range (Mydosh parameter φ = 0.022), such a shift is typical either for an insulating spin-glass or the presence of slow dynamics [30].…”

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confidence: 90%

Physical realization of a quantum spin liquid based on a complex frustration mechanism

et al. 2016

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Unlike conventional magnets where the magnetic moments are partially or completely static in the ground state, in a quantum spin liquid they remain in collective motion down to the lowest temperatures. The importance of this state is that it is coherent and highly entangled without breaking local symmetries. Such phenomena is usually sought in simple lattices where antiferromagnetic interactions and/or anisotropies that favor specific alignments of the magnetic moments are frustrated by lattice geometries incompatible with such order e.g. triangular structures. Despite an extensive search among such compounds, experimental realizations remain very few. Here we describe the investigation of a novel, unexplored magnetic system consisting of strong ferromagnetic and weaker antiferromagnetic isotropic interactions as realized by the compound Ca10Cr7O28. Despite its exotic structure we show both experimentally and theoretically that it displays all the features expected of a quantum spin liquid including coherent spin dynamics in the ground state and the complete absence of static magnetism.A quantum spin liquid is a macroscopic lattice of interacting magnetic ions with quantum spin number S=½, whose ground state has no static long-range magnetic order, instead the magnetic moments fluctuate coherently down to the lowest temperatures [1, 2]. It contrasts with the static long-range magnetically ordered ground states usually observed, and also with spin glass states where the spins are frozen into static short-range ordered configurations [3]. The excitations are believed to be spinons which have fractional quantum spin number S=½, and are very different from spin-waves or magnons that possess quantum spin number S=1 and are the characteristic excitations of conventional magnets. Spin liquids exist in one-dimensional magnets and the chain of spin-½ magnetic ions coupled by nearestneighbor, Heisenberg (isotropic), antiferromagnetic interactions is a well-established example [4]. This system has no static long-range magnetic order and the excitations are spinons. There is no energetic reason for the spinons to bind together, indeed if a spin-1 excitation is created e.g. by reversing a spin in the chain, it fractionalizes into two spin-½ spinons [5][6][7][8][9][10][11][12].The existence of spin liquids in dimensions greater than one is much less established. While static order does not occur in one-dimensional magnets, conventional two-and three-dimensional magnets order at temperatures at or above zero Kelvin [13]. This order can be suppressed by introducing competition (known as frustration) between the interactions that couple the magnetic ions. Geometrical frustration is achieved when the magnetic ions are located on lattices constructed from triangular motifs and are coupled by antiferromagnetic interactions. The antiferromagnetic coupling favors antiparallel spin alignment between nearest neighbor spins which can never be fully satisfied since the number of spins around the triangle is odd. This typically leads to h...

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“…Experimental studies on honeycomb iridates showed that the substitution of Ir 4+ by nonmagnetic ions, such as Ti 4+ in Li 2 Ir 1−x Ti x O 3 and Na 2 Ir 1−x Ti x O 3 , and also by strongly spin-orbit-coupled magnetic ions, e.g. Ru 4+ in Na 2 Ir 1−x Ru x O 3 , changes the antiferromagnetic zigzag state into a spin-glass state 34,35 . Via Monte Carlo calculations on the Kitaev-Heisenberg model this formation of a spin-glass state under the substitution of the magnetic ion by a nonmagnetic ion 36 or by magnetic ions 37 has successfully been rationalized.…”

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confidence: 99%

Spin-glass state and reversed magnetic anisotropy induced by Cr doping in the Kitaev magnet α−RuCl3

et al. 2019

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Magnetic properties of the substitution series Ru1−xCrxCl3 were investigated to determine the evolution from the anisotropic Kitaev magnet α-RuCl3 with J eff = 1/2 magnetic Ru 3+ ions to the isotropic Heisenberg magnet CrCl3 with S = 3/2 magnetic Cr 3+ ions. Magnetization measurements on single crystals revealed a reversal of the magnetic anisotropy under doping, which we argue to arise from the competition between anisotropic Kitaev and off-diagonal interactions on the Ru-Ru links and approximately isotropic Cr-Ru and isotropic Cr-Cr interactions. In addition, combined magnetization, ac susceptibility and specific-heat measurements clearly show the destabilization of the long-range magnetic order of α-RuCl3 in favor of a spin-glass state of Ru1−xCrxCl3 for a low doping of x ⋍ 0.

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Fragile magnetic order in the honeycomb lattice IridateNa2IrO3revealed by magnetic impurity doping

Cited by 19 publications

References 32 publications

Spin-Glass Ground State in a Triangular-Lattice Compound YbZnGaO4

Spin-Glass Ground State in a Triangular-Lattice Compound YbZnGaO4

Physical realization of a quantum spin liquid based on a complex frustration mechanism

Spin-glass state and reversed magnetic anisotropy induced by Cr doping in the Kitaev magnet α−RuCl3

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