Unraveling magnetic interactions and the spin state in insulating 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi>La</mml:mi></mml:mrow><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mrow><mml:mi>CoNbO</mml:mi></mml:mrow><mml:mn>6</mml:mn></mml:msub></mml:math>

Kumar, Ajay; Dhaka, R. S.

doi:10.1103/physrevb.101.094434

Cited by 35 publications

(80 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The evolution of this λ-like peak is attributed to the enhancement in the long-range AFM ordering below Néel temperature (T N ) for the x 0.6 samples as also evident in the magnetization measurements presented in Ref. [39]. Note that La substitution at Sr site converts Co valence state from 3+ (x = 0) to 2+ in the x = 1 sample [39].…”

Section: Resultssupporting

confidence: 53%

“…[39]. Note that La substitution at Sr site converts Co valence state from 3+ (x = 0) to 2+ in the x = 1 sample [39]. Interestingly, for the x = 1 sample [T N = 14.7(1) K], Co is present only in the 2+ oxidation state and due to the weak crystal field, 28-fold degenerate free ion 4 F term (S=3/2; L=3) of Co 2+ (3d 7 ) splits into 12-fold degenerate 4 T 1g ground term with effective orbital angular momentum ( L)=1.…”

Section: Resultsmentioning

confidence: 99%

“…Polycrystalline samples of Sr 2−x La x CoNbO 6 (x = 0-1) were synthesized in single phase by solid-state route using stoichiometric amounts of SrCO 3 , Co 3 O 4 , Nb 2 O 5 , La 2 O 3 and final sintering at 1300 0 C, more details of preparation and characterization can be found in [39]. The temperature and magnetic field dependent heat capacity using relaxation technique (1.8-300 K and up to 9 Tesla), dc-magnetic susceptibility in both zero field cooled (ZFC) and field cooled warming (FCW) modes, ac-susceptibility measurements at different excitation frequencies, and time dependent magnetization [M(t)] in different protocols [i.e.…”

Section: Methodsmentioning

confidence: 99%

“…However, Bos et al have studied the almost ordered antiferromagnetic Co 2+ -Nb 5+ double perovskite systems (LaA)CoNbO 6 (A=Ca, Sr, and Ba) using magnetization and neutron powder diffraction (NPD) measurements and report an enhancement in the geometrical frustration with increase in the ionic radii of A-site cations [7]. More recently, we have studied the evolution of the antiferrromagnetic insulating ground state in the Sr 2−x La x CoNbO 6 (x = 0-1) samples as a result of the enhancement in Co 2+ concentration and hence B-site ordering with the La substitution [39] as well as with strain in thin films [40]. However, the evolution of the complex spin states of Co 3+ , ground magnetic state for the x 0.4, and order of magnetic phase transition in the x 0.6 samples remain unresolved [39].…”

Section: Introductionmentioning

confidence: 99%

“…More recently, we have studied the evolution of the antiferrromagnetic insulating ground state in the Sr 2−x La x CoNbO 6 (x = 0-1) samples as a result of the enhancement in Co 2+ concentration and hence B-site ordering with the La substitution [39] as well as with strain in thin films [40]. However, the evolution of the complex spin states of Co 3+ , ground magnetic state for the x 0.4, and order of magnetic phase transition in the x 0.6 samples remain unresolved [39].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Evidence of discrete energy states and cluster-glass behavior in Sr$_{2-x}$La$_x$CoNbO$_6$

Kumar,

Schwarz,

Ehrenberg

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

We report the detailed analysis of specific heat [CP(T)] and ac-susceptibility for magnetically frustrated Sr2−xLaxCoNbO6 (x = 0-1) double perovskites to understand low temperature complex magnetic interactions and their evolution with x. Interestingly, the observed Schottky anomaly in the x 0.4 samples shifts gradually towards higher temperature with magnetic field as well as x, and the analysis reveal the persistence of the discrete energy states in these samples resulting from the spin-orbit coupling and octahedral distortion. Moreover, the extracted values of Landé gfactor indicate the existence of high-spin state Co 3+ ions close to non-magnetic low-spin state. The specific heat data show the λ-type anomaly for the x 0.6 samples due to evolution of the long range antiferromagnetic ordering. Our analysis of low temperature CP(T) data for the x 0.6 samples demonstrate the 3D isotropic Heisenberg antiferromagnetic (AFM) interactions and the temperature induced second order AFM-paramagnetic phase transition. More interestingly, we demonstrate the presence of the free Co 2+ like Kramers doublet ground state in the x =1 sample. Further, the ac susceptibility and time evolution of the magnetization data reveal the low temperature cluster-glass like behavior in the x = 0-0.4 samples, where spin-spin correlation strength decreases with x.

show abstract

Section: Resultssupporting

confidence: 53%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%