Magnetic susceptibility study of the heavy rare-earth stannate pyrochlores

Bondah-Jagalu, V.; Bramwell, S. T.

doi:10.1139/cjp-79-11-12-1381

Cited by 12 publications

(5 citation statements)

References 28 publications

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“…For both La or Nd on the A−site, Hf 4+ , Sn 4+ and Zr 4+ form pyrochlore ground state ternary structures. The remaining, Nb 5+ , Ta 5+ , Ti 4+ , and Sc 3+ form in the fergusonite, LaTaO 4 (NdTaO 4 ), perovskite-related layered orthorhombic (PRLO), and classical perovskite structures, respectively [21][22][23][24][25][26][27][28][29][30][31][32][33]. Experimentally observed ground state structures for every compound are tabulated in the Supporting Information.…”

Section: A Structure and Enthalpies Of Mixingmentioning

confidence: 99%

Computationally accelerated discovery of high entropy pyrochlore oxides

Pitike

Macias

Eisenbach

et al. 2021

Preprint

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High entropy ceramics provide enhanced flexibility for tailoring a wide range of physical properties, emerging from the diverse chemical and configurational degrees of freedom. Expanding upon the endeavors of recently synthesized high entropy ceramics in rock salt, fluorite, spinel and perovskite structures, we explore the relative feasibility of formation of high entropy pyrochlore oxides, A2B2O7, with multi-cation occupancy of the B-site, estimated from first principles based thermodynamic descriptors. Subsequently, we used Monte Carlo simulations to estimate the phase composition, oxygen vacancy concentration and local ionic segregation as a function of temperature and oxygen partial pressure. In parallel, we have investigated the synthesis of several multicomponent oxides with a pyrochlore composition, related to our computational investigations, resulting in several high purity pyrochlore oxides, in some cases with minor impurity phases. Ultimately, our approach allows us to evaluate potential impurity phases, ionic disorder and oxygen vacancy concentration in response to the experimental variables, thereby making realistic predictions that can direct and accelerate experimental synthesis of novel multicomponent ceramics.

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Section: A Structure and Enthalpies Of Mixingmentioning

confidence: 99%

Computationally accelerated discovery of high entropy pyrochlore oxides

Pitike

Macias

Eisenbach

et al. 2021

Preprint

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“…To further investigate the nature of the Ir magnetic order and its coupling to the rare-earth sublattice, we focused our attention on Er 2 Ir 2 O 7 and Tb 2 Ir 2 O 7 [17], displaying large magnetic moments on the rare-earth site and different types of anisotropy. In other pyrochlore families, like the titanates and stannates, the Er and Tb based compounds indeed show distinct magnetic ground states [18][19][20][21][22] and are thus expected to respond differently to the Ir molecular field.…”

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confidence: 99%

Anisotropy-Tuned Magnetic Order in Pyrochlore Iridates

et al. 2015

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The magnetic behavior of polycrystalline samples of Er(2)Ir(2)O(7) and Tb(2)Ir(2)O(7) pyrochlores is studied by magnetization measurements and neutron diffraction. Both compounds undergo a magnetic transition at 140 and 130 K, respectively, associated with an ordering of the Ir sublattice, signaled by thermomagnetic hysteresis. In Tb(2)Ir(2)O(7), we show that the Ir molecular field leads the Tb magnetic moments to order below 40 K in the all-in-all-out magnetic arrangement. No sign of magnetic long-range order on the Er sublattice is evidenced in Er(2)Ir(2)O(7) down to 0.6 K where a spin freezing is detected. These contrasting behaviors result from the competition between the Ir molecular field and the different single-ion anisotropy of the rare-earth elements on which it is acting. Additionally, this strongly supports the all-in-all-out iridium magnetic order.

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“…Curie-Weiss fits to higher temperature magnetization data for [25]. Figure 2 shows the low temperature (T < 1.5 K) ac susceptibility of Tb 2 Sn 2 O 7 in the absence of an applied static magnetic field.…”

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confidence: 99%

Low-temperature dynamic freezing and the fragility of ordering in Tb2Sn2O7

et al. 2011

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We have probed the low temperature magnetic behavior of the ordered spin ice material Tb 2 Sn 2 O 7 through ac magnetic susceptibility measurements of both the pure material and samples with small percentages of Ti substituted on the Sn sublattice. We observe a clear signature for the previously reported ordering transition at T C = 850 mK, as well as evidence for dynamic freezing at temperatures well below T C , confirming the persistence of significant magnetic fluctuations deep in the spin-ordered regime. The long range ordering transition was completely suppressed with as little as 5% Ti for Sn substitution, and 10% Ti substitution resulted in a spin-glass-like spin freezing transition near 250 mK. The results demonstrate that the long range magnetic ordering is surprisingly fragile in this system. shown a transition to a long-range ordered state at T C ~ 850 mK [11]. The ordered state results from effective ferromagnetic interactions between the spins in combination with <111> single-ion spin anisotropy due to the local crystal fields, yielding an apparent ordered spin ice state, i.e., two spins pointing in and two pointing out of each tetrahedron [11,12]. Unlike the canonical spin ice materials, such as Dy 2 Ti 2 O 7 and Ho 2 Ti 2 O 7 , the spins in Tb 2 Sn 2 O 7 are canted by ~13.3 degrees off the local <111> axis [13]. Despite the clear indications of spin-ordering, several studies have also reported the presence of significant spin fluctuations well below T C [14,15,16,17,18]. Here we report measurements of the low temperature ac magnetic susceptibility of pure Tb 2 Sn 2 O 7 , as well as samples with disorder introduced by partial substitution of Ti on the Sn site, i.e., of the form Tb 2 Sn 2-x Ti x O 7 . Our data probe the spin system on a longer time scale than previous studies, and demonstrate the existence of low frequency dynamic behavior well below ordering temperature. In the Ti-substituted samples, the introduction of as little as 5% Ti (x = 0.1) appears to completely suppress the long range

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Magnetic susceptibility study of the heavy rare-earth stannate pyrochlores

Cited by 12 publications

References 28 publications

Computationally accelerated discovery of high entropy pyrochlore oxides

Computationally accelerated discovery of high entropy pyrochlore oxides

Anisotropy-Tuned Magnetic Order in Pyrochlore Iridates

Low-temperature dynamic freezing and the fragility of ordering in Tb2Sn2O7

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