Electronic Structure and Bulk Spin-Valve Behavior in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">C</mml:mi><mml:msub><mml:mi mathvariant="normal">a</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mi mathvariant="normal">R</mml:mi><mml:msub><mml:mi mathvariant="normal">u</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:math>

Singh, David J.; Auluck, S.

doi:10.1103/physrevlett.96.097203

Cited by 42 publications

(33 citation statements)

References 28 publications

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“…24 Below the spin-flop transition field B c , the probed AFM structure is consistent with the model previously proposed for Ca 3 Ru 2 O 7 by DFT calculations 23 and powder neutron diffraction studies, 14 i.e. FM bilayers, with magnetic moments oriented along the b-axis, are stacked antiferromagnetically along the c-axis (This phase was labeled AFM-b in Ref.…”

Section: Introductionsupporting

confidence: 67%

“…19,21 The giant/colossal magnetoresistance has previously been attributed to the bulk spin-valve effect resulting from a spin-flop transition. 22,23 However, the bulk spin-valve effect model alone cannot explain why the larger colossal magnetoresistance is observed for fields along the hardaxis, contrary to general expectations for a spin-valve model.…”

Section: Introductionmentioning

confidence: 42%

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Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2O
Fobes
¹
,
Jin
²
,
Qu
³

et al. 2011
Phys. Rev. B
10
1
9
0
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We have performed systematic in-plane angle dependent c-axis transverse magnetotransport measurements on the double layered ruthenate Ca3Ru2O7 throughout a broad field and temperature range. Our results reveal the magnetic states unusually evolve with in-plane rotation of magnetic field. When magnetic field is applied along the b-axis we probe crossover magnetic states in close proximity to phase boundaries of long-range ordered antiferromagnetic (AFM) states. These crossover magnetic states are characterized by short-range antiferromagnetic order and switch to polarized paramagnetic states at critical angles as the in-plane field is rotated from the b-to aaxis. Additionally, we observe bulk spin valve behavior resulting from spin-flop transitions tuned by in-plane rotation of magnetic field. Our results highlight the complex nature of the spin-charge coupling in Ca3Ru2O7 and posts a challenging question: why does the change of magnetic field orientation result in magnetic phase transitions.

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Section: Introductionsupporting

confidence: 67%

Section: Introductionmentioning

confidence: 42%

Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2O
Fobes
¹
,
Jin
²
,
Qu
³

et al. 2011
Phys. Rev. B
10
1
9
0
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“…16 Structural irreversibility seen in our data would then follow from strong magnetoelastic coupling in this material. 17 A spin-flop magnetic phase might also explain the path dependence in phase space that was mentioned earlier. That is, in the fixed-B measurement, the T = 44.3 K and B = 8 T point in phase space is reached from within the spin-polarized phase, while in the fixed-T measurement, the path includes the proposed spinflop phase.…”

mentioning

confidence: 92%

Spin-charge-lattice coupling near the metal-insulator transition inCa3Ru2O7

Nelson

Bohnenbuck

et al. 2007

Phys. Rev. B

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We report x-ray scattering studies of the c-axis lattice parameter in Ca 3 Ru 2 O 7 as a function of temperature and magnetic field. These structural studies complement published transport and magnetization data, and therefore elucidate the spin-charge-lattice coupling near the metal-insulator transition. Strong anisotropy of the structural change for field applied along orthogonal in-plane directions is observed. Competition between a spin-polarized phase that does not couple to the lattice and an antiferromagnetic metallic phase that does gives rise to a rich behavior for B ʈ b.The interplay of spin, charge, and lattice degrees of freedom is believed to underlie the complicated physics exhibited by many correlated electron systems, such as the colossal magnetoresistant manganites. 1 An exciting corollary of this interplay is the tunability of ground state propertiese.g., inducing a metal-insulator transition via application of magnetic field or controlling magnetic properties via strainthat has the potential to turn these systems into technologically useful electronic materials. 2 Optimization of the useful properties, however, requires a thorough understanding of the spin-charge-lattice coupling in these materials.Bilayer Ca 3 Ru 2 O 7 provides a particularly rich example of spin-charge-lattice coupling in a correlated electron system. Metallic Ca 3 Ru 2 O 7 orders antiferromagnetically at T N = 56 K and exhibits a metal-insulator transition at T m−i =48 K, 3 although a quasi-two-dimensional metallic ground state has been reported for T Ͻ 30 K. 4 At T m−i , a collapse of the c-axis lattice parameter is observed, 5 with a concomitant in-plane expansion. 6 This structural change is surprising in that a smaller c-axis lattice parameter is expected to increase the orbital overlap, which would result in a stabilization of the metallic state. Neutron powder diffraction studies suggest, however, that a decrease in the Ru-O-Ca bond angle that decreases the interlayer electron transfer may explain this unexpected behavior. 6 Finally, a spin reorientation transition, which was indicated by magnetic susceptibility measurements, 3 occurs in the vicinity of T m−i . 4,7-9 Neutron powder diffraction 6 confirmed the proposed low-temperature magnetic structure 7 as consisting of ferromagnetic bilayers, antiferromagnetically coupled and with moments along the orthorhombic b axis, using the Bb2 1 m notation of space group 36, for which a Ͻ b. 10 The spin reorientation rotates the moments such that they lie along a for T Ͼ T m−i .The confluence of spin reorientation, structural change, and a metal-insulator transition clearly demonstrates the interplay of the spin, charge, and lattice degrees of freedom in Ca 3 Ru 2 O 7 near T m−i , which has been the focus of recent transport and magnetization measurements. 7,11 In this Brief Report, we further this investigation by reporting x-ray scattering studies of the c-axis lattice parameter in Ca 3 Ru 2 O 7 , with applied magnetic fields of up to 10 T. Combining this information with pre...

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“…In general, substitution of Sr 2+ with the smaller Ca 2+ ions tends to increase distortion and tilting of the octahedral with a resulting decrease in valence band width and tendency toward antiferromagnetic ordering [3][4][5][6]. The interactions are strong functions not only of the cation, however, but also of the number of layers n, even though the basal plane structures for different n are very similar [3].…”

mentioning

confidence: 99%

“…x=1) salt, there is no resulting long range spin order at ambient pressure, but longitudinal strain can induce a ferromagnetic state [5,10]. In the pure calcium (x=0) salt, the spins order ferromagnetically within the bilayers, but the interlayer (c-axis) interactions are predominantly antiferromagnetic, leading to a Néel transition at T N = 56 K with spin polarization along the b-axis [6,[11][12][13]. With further cooling, the spin polarization rotates within the plane toward the a-axis [13,14].…”

mentioning

confidence: 99%

Specific heat of (Ca1−xSrx)3Ru2O7 single crystals

Varadarajan

Saito

Durairaj

et al. 2007

Solid State Communications

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We have measured the specific heat of crystals of (Ca 1-x Sr x ) 3 Ru 2 O 7 using ac-and relaxation-time calorimetry. Special emphasis was placed on the characterization of the Néel (T N =56 K) and structural (T c = 48 K) phase transitions in the pure, x=0 material.While the latter is believed to be first order, detailed measurements under different experimental conditions suggest that all the latent heat (with L ~ 0.3 R) is being captured in a broadened peak in the effective heat capacity. The specific heat has a mean-fieldlike step at T N , but its magntitude (∆c P ~ R) is too large to be associated with a conventional itinerant electron (e.g. spin-density-wave) antiferromagnetic transition, while its entropy is too small to be associated with full ordering of localized spins. The T N transition broadens with Sr substitution while its magnitude decreases slowly. On the other hand, the entropy change associated with the T c transition decreases rapidly with Sr substitution and is not observable for our x=0.58 sample. PACS: 71.27.+a, 75.40.Cx, 65.40 The spin-structure of the double-layer, n =2, compounds have been especially unusual. In the pure strontium (i.e. x=1) salt, there is no resulting long range spin order at ambient pressure, but longitudinal strain can induce a ferromagnetic state [5,10]. In the pure calcium (x=0) salt, the spins order ferromagnetically within the bilayers, but the interlayer (c-axis) interactions are predominantly antiferromagnetic, leading to a Néel transition at T N = 56 K with spin polarization along the b-axis [6,[11][12][13]. With further cooling, the spin polarization rotates within the plane toward the a-axis [13,14]. There is a second, more unusual, phase transition at T c = 48 K; here all components of the susceptibility drop abruptly upon cooling through T c [11,14], which has been suggested to be due to formation of a charge-density-wave [15], while the lattice contracts along c by [3,11,20]. All crystals studied were characterized by single crystal or powder x-ray diffraction, EDS and TEM,indicating good crystal quality with no impurities or intergrowths or significant clustering of strontium ions. Magnetic and transport properties were measured using a Quantum Design MPMS XL 7T magnetometer. (Since the shape of all crystals studied in this work is essentially cubic, the demagnetizing factor for all samples and all three principal crystallographic axes is expected to be the same, and is not included in our the susceptibility is almost isotropic in the ab-plane (suggesting that the RuO 6 octahedra are almost "untilted", as in the pure Sr compound) with peaks in M at T p ~ 50 K followed by weak minima (T~ 40 K) and relatively high susceptibilities at lower temperatures.Only small anomalies are observed in the resistance at these temperatures, and the shape of the magnetic anomalies [4] suggests that spin ordering is complex but incomplete. A more complete discussion of the substitution-dependence of the resistance and magnetization, including their field dependence...

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Electronic Structure and Bulk Spin-Valve Behavior inCa3Ru2O7

Cited by 42 publications

References 28 publications

Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2O
Fobes
¹
,
Jin
²
,
Qu
³

et al. 2011
Phys. Rev. B
10
1
9
0
View full text Add to dashboard Cite

Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2O
Fobes
¹
,
Jin
²
,
Qu
³

et al. 2011
Phys. Rev. B
10
1
9
0
View full text Add to dashboard Cite

Spin-charge-lattice coupling near the metal-insulator transition inCa3Ru2O7

Specific heat of (Ca1−xSrx)3Ru2O7 single crystals

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Electronic Structure and Bulk Spin-Valve Behavior inCa3Ru2O7

Cited by 42 publications

References 28 publications

Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2OFobes1, Jin2, Qu3 et al. 2011Phys. Rev. B10190View full textAdd to dashboardCite

Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2OFobes1, Jin2, Qu3 et al. 2011Phys. Rev. B10190View full textAdd to dashboardCite

Spin-charge-lattice coupling near the metal-insulator transition inCa3Ru2O7

Specific heat of (Ca1−xSrx)3Ru2O7 single crystals

Contact Info

Product

Resources

About

Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2O
Fobes
¹
,
Jin
²
,
Qu
³

et al. 2011
Phys. Rev. B
10
1
9
0
View full text Add to dashboard Cite

Magnetic phase transitions and bulk spin-valve effect tuned by in-plane field orientation in Ca3Ru2O
Fobes
¹
,
Jin
²
,
Qu
³

et al. 2011
Phys. Rev. B
10
1
9
0
View full text Add to dashboard Cite