Multiferroic properties and magnetic structure of Sm<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow /><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>Y<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow /><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>MnO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" displa

O’Flynn, Daniel; Tomy, C. V.; Lees, Martin R.; Daoud‐Aladine, A.

doi:10.1103/physrevb.83.174426

Cited by 45 publications

(25 citation statements)

References 26 publications

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“…Verification that the new AF3 phase must exist is achieved by a Landautype model based on rigorous symmetry arguments. Furthermore, the occurrence of such a collinear state, just above a non-collinear state, is confirmed in well studied frustrated RMnO 3 and RMn 2 O 5 systems [20][21][22], and the kagomé compound Ni 3 V 2 O 8 [23]. Finally, the proposed model accounts for the experimental phase diagram of CuO determined in this work and is potentially useful for the description of other monoclinic multiferroic systems, in particular MnWO 4 [24] and AMSi 2 O 6 [25].…”

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confidence: 75%

Magnetic Phase Diagram of CuO via High-Resolution Ultrasonic Velocity Measurements

et al. 2012

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High resolution ultrasonic velocity measurements have been used to determine the temperaturemagnetic-field phase diagram of the monoclinic multiferroic CuO. A new transition at TN3 = 230 K, corresponding to an intermediate state between the antiferromagnetic non-collinear spiral phase observed below TN2 = 229.3 K and the paramagnetic phase, is revealed. Anomalies associated with a first order transition to the commensurate collinear phase are also observed at TN1 = 213 K. For fields with B b, a spin-flop transition is detected between 11 T -13 T at lower temperatures. Moreover, our analysis using a Landau-type free energy clearly reveals the necessity for an incommensurate collinear phase between the spiral and the paramagnetic phase. This model is also relevant to the phase diagrams of other monoclinic multiferroic systems.PACS numbers: 75.30.Kz, 75.85.+t, 75.30.Gw Multiferroic phenomena have been a subject of intense interest in recent decades arising from opportunities to explore new fundamental physics as well as possible technological applications [1][2][3]. Coupling between different ferroic orders has been proven to be driven by several different types of mechanisms. In particular, multiferroics with a spiral spin-order-induced ferroelectricity have revealed high spontaneous polarization and strong magnetoelectric coupling [4,5]. Cupric oxide (CuO), the subject of this letter, was characterized as a magnetoelectric multiferroic four years ago when it was shown that its ferroelectric order is induced by the onset of a spiral antiferromagnetic (AFM) order at an unusually high temperature of 230 K [3]. Thus far, two AFM states have been reported, a low temperature (T N 1 ∼ 213 K) AF1 commensurate collinear state with the magnetic moments along the monoclinic b axis and an AF2 incommensurate spiral state with half of the magnetic moments in the ac plane (T N 2 ∼ 230 K) [3,6,7]. However, the authors of the neutron diffraction measurements [6] Encouraged by recent experiments on other multiferroic systems using ultrasonic measurements [11], we measured the temperature and field dependence of the velocity of transverse modes in order to determine the magnetic phase diagram of CuO. A new transition is detected at T N 3 = 230 K just above the AF2 spiral phase observed at T N 2 = 229.3 K, while the first order transition is observed at T N 1 = 213 K. Furthermore, dielectric constant measurements confirm that only the spiral phase (between T N 1 and T N 2 ) supports a spontaneous electric polarization. In addition, we report on a spin-flop transition in the low temperature AF1 collinear phase when B b. Thus, based on these findings, a new magneticfield vs temperature phase diagram is proposed for CuO. In order to elucidate the possible nature of the AFM states observed in CuO, a non-local Landau-type free energy is also developed for CuO and similar monoclinic multiferroics. This approach has been very successful in explaining the magnetic phase diagrams of other multiferroic systems [12][13][14]. In contrast w...

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confidence: 75%

Magnetic Phase Diagram of CuO via High-Resolution Ultrasonic Velocity Measurements

et al. 2012

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“…In the parent compound GdMnO 3 , a step‐like anomaly instead of a peak at ~23 K has been reported, associated to an incommensurate sinusoidal to an A‐type antiferromagnetic transition . On the other hand, a peak in ε′( T ) has been reported for the multiferroic systems RMnO 3 (TbMnO 3 and DyMnO 3 ) and (RR′)MnO 3 (Eu 1− x Y x MnO 3 , Tb 1− x Gd x MnO 3 and Sm 1 −x Y x MnO 3 ). This peak is associated with improper ferroelectric transition induced by magnetic transition.…”

Section: Resultsmentioning

confidence: 99%

“…Extensive dielectric studies have been carried out on RMnO 3 system and mixed crystals . Strong anomaly in the temperature‐dependent dielectric constant ε( T ) has been reported only about T N2 (Mn 3+ ).…”

Section: Introductionmentioning

confidence: 99%

Studies on dielectric relaxation in ceramic multiferroic Gd_1−xY_xMnO₃

et al. 2017

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Dielectric study over a broadband was carried out from 10 to 70 K on ceramic Gd1−xYxMnO3 (x=0.2, 0.3 and 0.4). For all the compositions, a prominent sharp peak about ~18 K was observed in the temperature dependence of both ε′(T) and ε″(T) at all frequencies, indicating a long‐range ferroelectric (FE) transition. Using Cole‐Cole fit to the permittivity data, the relaxation time τ and the dielectric strength ∆ε were estimated. Temperature variation of τ(T) in the Arrhenius representation is found to be nonlinear (non‐Debyean relaxation), with increasing barrier‐activation energy over successive temperature‐windows. Interestingly, for all the compositions, we witness a jump in τ(T) about the ferroelectric transition temperature, concurred by a broad‐maximum in ∆ε(T),signifying the critical slow down of relaxations near long‐range FE‐correlations.

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“…The typical examples include Eu 1Àx Y x MnO 3 , [16][17][18] Sm 1Àx Y x MnO 3 (Ref. 19), and Gd 1Àx Tb x MnO 3 . 20 This strategy allows more multiferroic manganites of CS order to be synthesized beyond TbMnO 3 and DyMnO 3 .…”

Section: Introductionmentioning

confidence: 99%