Manometer extension for high pressure measurement: Nuclear quadrupole resonance study of Cu2O with a modified Bridgman anvil cell up to 10 GPa

Fukazawa, Hideto; Yamatoji, N; Kohori, Yoh; Terakura, C.; Takeshita, Nao; Tokura, Y.; Takagi, H.

doi:10.1063/1.2426875

Cited by 31 publications

(19 citation statements)

References 17 publications

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“…13) Although it should be revealed by additional experimental approaches whether this superconductivity is intrinsic or not, it is clear that the investigation of this compound under pressure is quite important and that the subsequent NMR studies of BaFe 2 As 2 under high pressure requires such high pressure of 10 GPa. The recent development of a high-pressure NMR/NQR technique by the authors' group 14,15) will help provide further insights into our understanding of this interesting iron-based pnictide.…”

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confidence: 99%

Magnetic Property of BaFe₂As₂Probed by⁷⁵As NMR

et al. 2008

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We report the detailed analysis of zero-external-field (ZF) 75 As nuclear-magnetic-resonance (NMR) measurement of the ternary iron arsenide BaFe2As2. The ZF 75 As-NMR spectrum clearly revealed that the magnetically ordered state is commensurate. Its internal magnetic field at the As site is 1.39(2) T. KEYWORDS: BaFe2As2, magnetic transition, nuclear magnetic resonanceThe discovery of superconductivity in F-doped LaFeAsO 1) has accelerated further investigations of the related superconductors.2-4) The common feature of these compounds is the possession of a FeAs layer which is analogous to the CuO 2 plane in high-superconductingtransition-temperature (high-T c ) cuprates. Soon after the intensive investigations of the oxypnictides, the oxygen-free iron pnictide BaFe 2 As 2 5) was proposed as the next candidate parent material of superconductor with high T c . The crystal structure of these pnictides is the ThCr 2 Si 2 -type structure. This structure possesses a similar FeAs layer to that realized in LaFeAsO. Moreover, this material exhibits spin density wave (SDW) anomaly at T SDW = 140 K (BaFe 2 As 2 ).5, 6) It is important to note that the compound exhibits structural phase transition from tetragonal (I4/mmm) to orthorhombic (F mmm) as well as SDW anomaly.5, 6) The anomaly is reported to be of the second order.5) However, recent neutron diffraction measurements of BaFe 2 As 2 reported the hysteresis of a tetragonal (220) peak between the oncooling sequence and the on-warming sequence, which indicates the structural order at T SDW is of the first order as in BaFe 2 As 2 . 6)The most striking feature of the above compound is that the SDW anomaly disappears and the superconductivity indeed sets in by hole doping, for example, K substitution for Ba.7) In order to understand the superconductivity in these doped oxygen-free iron-based pnictides, it is also important to study the magnetic and electronic properties of the parent material. Hence, we performed 75 As nuclear-magnetic-resonance (NMR) measurements of BaFe 2 As 2 . 8)In our previous letter, we reported the 75 As-NMR spectra of BaFe 2 As 2 at various temperatures and the temperature T dependence of the spin-lattice relaxation rate 1/T 1 of 75 As. 75 As-NMR spectra clearly revealed that magnetic transition occurs at around 131 K in our samples, which corresponds to the emergence of spin density wave. The T dependence of the internal magnetic field H int suggested that the transition is likely of the first order. We also deduced from the defference of the * E-mail address: hideto@nmr.s.chiba-u.ac.jp linewidth of the highly oriented powder and partially oriented powder that the H int at the As site is parallel to c-axis. The evaluated hyperfine coupling constant A d ab originating from the coupling between 75 As nuclear spin and 3d conduction electron of Fe was +19(2) kOe/µ B , which was the same magnitude of coupling constant as that reported for 75 As-NMR of LaFeAsO 0.9 F 0.1 .9) The critical slowing-down phenomenon in 1/T 1 was not pronounced in this materi...

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confidence: 99%

Magnetic Property of BaFe₂As₂Probed by⁷⁵As NMR

et al. 2008

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“…Although superconductivity should be discussed with the data of T dependence of T À1 1 , if superconductivity is induced even at 2.49 GPa, we may roughly expect a sufficient increase in T 1 due to the gap formation of superconductivity. Therefore, we should continue the NMR measurements at P values beyond 3 GPa in order to determine the magnetic phase diagram and ground state of BaFe 2 As 2 under P with a Bridgman anvil cell 17) and a mini cubic anvil apparatus, 18) which are now in progress. The T-P phase diagram of BaFe 2 As 2 determined from resistivity anomalies.…”

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confidence: 99%

Suppression of Magnetic Order by Pressure in BaFe₂As₂

et al. 2008

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1)has accelerated further investigations of the related superconductors. [2][3][4] The common feature of these compounds is the possession of an FeAs layer, which is analogous to the CuO 2 plane in high-superconducting-transition-temperature (high-T c ) cuprates. Soon after the intensive investigations of the oxypnictides, the oxygen-free iron pnictide BaFe 2 As 2 5)was proposed as the next-candidate parent material of superconductors with high T c . The crystal structure of this pnictide is the ThCr 2 Si 2 -type structure and possesses a similar FeAs layer to that realized in LaFeAsO. Moreover, this material exhibits spin density wave (SDW) anomaly at T SDW ¼ 140 K (BaFe 2 As 2 ). 5,6) It is important to note that the compound exhibits structural phase transition from tetragonal (I4=mmm) to orthorhombic (Fmmm) as well as SDW anomaly. 5,6) The most striking feature of this compound is that the SDW anomaly disappears and superconductivity is induced by hole doping, for example, K substitution for Ba. 7) In addition, the pressure P-induced superconductivity in BaFe 2 As 2 has recently been reported by the magnetic susceptibility measurements at pressures of up to about 6 GPa. 8) Although it should be revealed by additional experimental approaches whether this superconductivity is intrinsic, it is clear that the investigation of this compound under pressure is important. To understand the relationship between the SDW instability and expected superconductivity in BaFe 2 As 2 , we performed resistivity and zero-externalfield (ZF)75 As nuclear-magnetic-resonance (NMR) measurements of BaFe 2 As 2 under high pressure.In our previous letter, we reported the 75 As-NMR spectra of BaFe 2 As 2 at various temperatures and the temperature T dependence of the spin-lattice relaxation rate 1=T 1 of 75 As under ambient pressure.9) 75 As-NMR spectra clearly revealed that magnetic transition occurs at around 131 K in our samples, which corresponds to the emergence of spin density wave. The T dependence of the internal magnetic field H int suggested that the transition is likely of the first order. We also deduced from the difference in linewidth between the highly and partially oriented powders that the H int at the As site is parallel to the c-axis. The steep decrease in 1=T 1 below T SDW was observed to be due to the gap formation of the SDW at a certain part of the Fermi surface. 1=T 1 below approximately 100 K was nearly proportional to T, which indicates the relaxation due to the remaining conduction electron at the Fermi level even below T SDW . In our previous paper, we also reported a ZF 75 As-NMR spectrum at 1.5 K.9,10) The ZF 75 As-NMR spectrum clearly revealed that the magnetically ordered state of this compound is commensurate. Furthermore, the center line of the ZF 75 As-NMR spectrum is a good measure of the H int at the As site.Polycrystalline BaFe 2 As 2 samples were synthesized by a high-temperature and high-pressure method. They were confirmed to be nearly single phase by X-ray diffraction analysis. Electrical resis...

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“…15) Reyes et al have established Cu 2 O-NQR as a suitable manometer in the temperature range 4 -300 K and for the pressure up to 2 GPa. 15) Fukazawa et al have extended the measurements up to 10 GPa at 1.6 K. 2) We found that the T-and P-dependences of 63 Q can be precisely fit to a formula, which is a refined version of the formula used by Wijin and Wildt 16) and by Reyes et al 15) based upon a simple phononic analysis. The Knight shift of 63 Cu shows a very small P-dependence, À10 ppm/GPa, therefore it can be used to determine the field values in the pressure cell during NMR experiments.…”

Section: Introductionmentioning

confidence: 99%

“…Although a few trials have been reported using modified Bridgeman 2,7) cells, moissanite anvil cell (MAC), 8) or diamond anvil cells (DAC), [9][10][11] problems still remain concerning the insufficient sample space, poor hydrostaticity, or inhomogeneity of the magnetic field due to magnetization of the cells. 7,10) In this paper, we report development of a new type of opposedanvil-cell which can be used to generate pressure up to 9 GPa over a volume of 7 mm 3 with the total cell size of 29 mm Â 41 mm.…”

Section: Introductionmentioning

confidence: 99%

“…For example, there is an order-of-thousand difference in the available sample space between the piston-cylinder-type cell, 1) which can be used to generate pressure less than 4 GPa, and the modified Bridgeman-type cell, 2) which can go up to 10 GPa. Thus, easy access to the pressure above 4 GPa is practically restricted to volume-insensitive experiments such as resistivity or optical measurements.…”

Section: Introductionmentioning

confidence: 99%

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Space Efficient Opposed-Anvil High-Pressure Cell and Its Application to Optical and NMR Measurements up to 9 GPa

et al. 2010

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We have developed a new type of opposed-anvil high pressure cell with substantially improved space efficiency. The clamp cell and the gasket are made of non-magnetic Ni-Cr-Al alloy. Non-magnetic tungsten carbide (NMWC) is used for the anvils. The assembled cell with the dimension 29 mm Â 41 mm is capable of generating pressure up to 9 GPa over a relatively large volume of 7 mm 3 . Our cell is particularly suitable for those experiments which require large sample space to achieve good signal-to-noise ratio, such as the nuclear magnetic resonance (NMR) experiment. Argon is used as the pressure transmitting medium to obtain good hydrostaticity. The pressure was calibrated in situ by measuring the fluorescence from ruby through a transparent moissanite (6H-SiC) window. We have measured the pressure and temperature dependences of the 63 Cu nuclear-quadrupole-resonance (NQR) frequency of Cu 2 O, the in-plane Knight shift of metallic tin, and the Knight shift of platinum. These quantities can be used as reliable manometers to determine the pressure values in situ during the NMR/NQR experiments up to 9 GPa.

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Manometer extension for high pressure measurement: Nuclear quadrupole resonance study of Cu2O with a modified Bridgman anvil cell up to 10 GPa

Cited by 31 publications

References 17 publications

Magnetic Property of BaFe₂As₂Probed by⁷⁵As NMR

Magnetic Property of BaFe₂As₂Probed by⁷⁵As NMR

Suppression of Magnetic Order by Pressure in BaFe₂As₂

Space Efficient Opposed-Anvil High-Pressure Cell and Its Application to Optical and NMR Measurements up to 9 GPa

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Manometer extension for high pressure measurement: Nuclear quadrupole resonance study of Cu2O with a modified Bridgman anvil cell up to 10 GPa

Cited by 31 publications

References 17 publications

Magnetic Property of BaFe2As2Probed by75As NMR

Magnetic Property of BaFe2As2Probed by75As NMR

Suppression of Magnetic Order by Pressure in BaFe2As2

Space Efficient Opposed-Anvil High-Pressure Cell and Its Application to Optical and NMR Measurements up to 9 GPa

Contact Info

Product

Resources

About

Magnetic Property of BaFe₂As₂Probed by⁷⁵As NMR

Magnetic Property of BaFe₂As₂Probed by⁷⁵As NMR

Suppression of Magnetic Order by Pressure in BaFe₂As₂