Phase transitions of MnO to 137 GPa

Kondo, Tadashi; Yagi, T.; Syono, Yasuhiko; Noguchi, Yuichi; Atou, Toshiyuki; Kikegawa, Takumi; Shimomura, Osamu

doi:10.1063/1.373045

Cited by 45 publications

(40 citation statements)

References 19 publications

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“…The remnant of distorted-B 1 phase, on the other hand, was observed well above 90 GPa to about 120-130 GPa. In contrast, the previous diffraction study suggested an "intermediate" phase in the pressure region between 90 and 120 GPa, without the characterization of crystal structure [7]. These pressure-induced structural/spectral changes of MnO observed in the present study, therefore, provide a coherent picture, suggesting the phase transitions from paramagnetic B 1 to antiferromagnetic dist-B 1 at 30 GPa, to paramagentic B 8 at 90 GPa, and to diamagnetic B 8 at 110 GPa.…”

Section: A the Mott Insulator-metal Transition Of Mno At 110 Gpacontrasting

confidence: 54%

Electronic Transitions in f-electron Metals at High Pressures:

Yoo¹,

Maddox²,

Lazicki³

et al. 2007

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This study was to investigate unusual phase transitions driven by electron correlation effects that occur in many f-band transition metals and are often accompanied by large volume changes: ~ 20% at the δ−α transition in Pu and 5-15% for analogous transitions in Ce, Pr, and Gd. The exact nature of these transitions has not been well understood, including the short-range correlation effects themselves, their relation to long-range crystalline order, the possible existence of remnants of the transitions in the liquid, the role of magnetic moments and order, the critical behavior, and dynamics of the transitions, among other issues. Many of these questions represent forefront physics challenges central to Stockpile materials and are also important in understanding the high-pressure behavior of other f-and d-band transition metal compounds including 3d-magnetic transition monoxide (TMO, TM=Mn, Fe, Co, Ni).The overarching goal of this study was, therefore, to understand the relationships between crystal structure and electronic structure of transition metals at high pressures, by using the nation's brightest third-generation synchrotron x-ray at the Advanced Photon Source (APS). Significant progresses have been made, including new discoveries of the Mott transition in MnO at 105 GPa and Kondo-like 4f-electron dehybridization and new developments of high-pressure resonance inelastic x-ray spectroscopy and x-ray emission spectroscopy. These scientific discoveries and technology developments provide new insights and enabling tools to understand scientific challenges in stockpile materials. The project has broader impacts in training two SEGRF graduate students and developing an university collaboration (funded through SSAAP). Scientific BackgroundThe f-electron metals, actinides and lanthanides alike, exhibit a profound change in character, both for individual metals as a function of compression, or across the series as a whole at ambient pressure. It is believed that this behavior is driven by strong 5f-electron correlation [1]. As we proceed through the series of the actinides, for example, two distinct parts of the series are discovered as illustrated in Fig. 1. The early part, from Th-Pu, shows a parabolic behavior of the equilibrium molar volume reminiscent of the d-transition metals, whereas the later part shows a more constant behavior of the specific volume as a function of atomic number. The similarity between the light actinides and the d-transition metals in this regard is governed by the fact that the light actinides and the d-transition metals both have delocalized electrons, f and d respectively. For the heavier actinides from americium and on, however, the 5f electrons are localized similar to the lanthanide series and their properties become quite different from that of the earlier actinides. The itinerant 5f electrons also show a distinguished difference compared to the 4d and 5d electrons; that is, their bandwidths are much narrower and in turn this leads to distortions in crystal structures of...

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Section: A the Mott Insulator-metal Transition Of Mno At 110 Gpacontrasting

confidence: 54%

Electronic Transitions in f-electron Metals at High Pressures:

Yoo¹,

Maddox²,

Lazicki³

et al. 2007

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“…Its diffraction pattern at 79 GPa and room temperature quenched from 2000 K turned to be the mixed peaks of CoO (this seems to be rhombohedrally distorted from B1 as Guo et al, 2002, reports) + SiO 2 (CaCl 2 -type). The variation of the diffraction peaks of CoO with increasing pressure at room temperature suggests that CoO has a B1 structure at high pressure and high temperature like FeO and MnO (Kondo et al, 2000(Kondo et al, , 2004. These results indicate that the stable form of CoSiO 3 is CoO …”

Section: Cosiomentioning

confidence: 49%

Stability of the perovskite structure and possibility of the transition to the post-perovskite structure in CaSiO3, FeSiO3, MnSiO3 and CoSiO3

Fujino

Nishio–Hamane

Suzuki

et al. 2009

Physics of the Earth and Planetary Interiors

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High pressure and high temperature experiments on CaSiO 3 , FeSiO 3 , MnSiO 3 and CoSiO 3 using a laser-heated diamond anvil cell combined with synchrotron X-ray diffraction were conducted to explore the perovskite structure of these compounds and the transition to the post-perovskite structure. The experimental results revealed that MnSiO 3 has a perovskite structure from relatively low pressure (ca. 20 GPa) similarly to CaSiO 3 , while the stable forms of FeSiO 3 and CoSiO 3 are mixtures of mono-oxide (NaCl structure) + high pressure polymorph of SiO 2 even at very high pressure and temperature (149 GPa and 1800 K for FeSiO 3 and 79 GPa and 2000 K for CoSiO 3 ). This strongly suggests that the crystal field stabilization energy (CFSE) of Fe 2+ with six 3d electrons and Co 2+ with seven 3d electrons at the octahedral site of mono-oxides favors a mixture of mono-oxide + SiO 2 over perovskite where Fe 2+ and Co 2+ would occupy the distorted dodecahedral sites having a smaller CFSE (Mn 2+ has five 3d electrons and has no CFSE).The structural characteristics that the orthorhombic distortion of MnSiO 3 perovskite decreases with pressure and the tolerance factor of CaSiO 3 perovskite (0.99) is far from the orthorhombic range suggest that both MnSiO 3 and CaSiO 3 perovskites will not transform to the CaIrO 3 -type post-perovskite structure even at the Earth's core-mantle boundary conditions, although CaSiO 3 perovskite has a potentiality to transform to the CaIrO 3 -type post-perovskite structure at still higher pressure as long as another type of transformation does not occur.

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“…The displacive phase transition has also been observed in FeO (5), MnO (24), and CoO (23) under high pressures. MnO and CoO displayed multiple phase transitions under high pressures (23,24). Nevertheless, the distorted B1 phases transform to the B1 structure upon laser heating, and the B1 structure transforms back to the distorted phases after temperature quench (Fig.…”

Section: Experimental Methodsmentioning

confidence: 99%

Stability of magnesiowüstite in Earth's lower mantle

Lin

Heinz

Mao

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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[(Mg,Fe)SiO 3 ] (1, 2), which together are likely the most important mineral assemblage of Earth's interior. The stability of the magnesiowüstite and silicate perovskite plays a crucial role in understanding the geophysical and geochemical properties of Earth. At ambient conditions, the end members of the MgOFeO (periclase-wüstite) system form a solid solution and have the same rock-salt (B1) structure. Periclase remains in the B1 structure to at least 227 GPa (3, 4). Wüstite transforms to a rhombohedral structure at pressures above 18 GPa at 300 K (5) and then to the NiAs or anti-NiAs structure (6-8). The topological difference between the pressure-temperature (P-T) phase diagrams of periclase and wüstite indicates that regions of two-phase equilibria should exist. A thermodynamically calculated P-T-composition phase diagram for the system suggests that an increase in pressure in the system would result in a gradual exsolution of an almost pure FeO and an Fe-depleted (Mg,Fe)O (9). Recent studies of three magnesiowüstites [(Mg 0.5 ,Fe 0.5 )O, (Mg 0.6 ,Fe 0.4 )O, and (Mg 0.8 ,Fe 0.2 )O] in an externally heated diamond anvil cell (DAC) up to 86 GPa and 1,000 K suggested that magnesiowüstite decomposes into Mg-rich and Fe-rich magnesiowüstites (10, 11). The decomposition of magnesiowüstite was proposed to occur at the P-T conditions of the lower mantle (10, 11) and to contribute significantly to the seismic-wave heterogeneity of the lower mantle (12, 13). On the other hand, no evidence for a phase transformation in (Mg 0.6 ,Fe 0.4 )O was found in shock-wave experiments to 201 GPa (14). Here we report the in situ study of structure and stability of magnesiowüstites at P-T conditions of the lower mantle. A rhenium or stainless steel gasket was preindented to a thickness of 30 m and then a hole of 220-m diameter was drilled in it. An amorphous boron and epoxy mixture (4:1 by weight) was filled and compressed in the hole. Subsequently, another hole of 100 m was drilled and used as the sample chamber. A sandwich configuration, consisting of dried NaCl as the thermal insulator and pressure medium on both sides of the sample, was used (16-18). The amorphous boron provided higher strength to create a deeper sample chamber, giving stronger x-ray diffraction from a thicker sample and better laser-heating spots attributable to thicker thermal insulating layers. ʈ Moreover, use of amorphous boron as an inner gasket also avoided unwanted x-ray diffraction peaks from Re or the stainless steel gasket. Experimental MethodsWe have used a double-sided Nd:YLF (neodymium: yttrium lithium fluoride) laser heating system, operating in multimode (TEM 00 ϩTEM 01 ), to heat the sample from both sides of a DAC at the 13-IDD GeoSoilEnviro-Consortium for Advanced Radiation Sources (GSECARS) sector of the Advanced Photon Source, Argonne National Laboratory (18). The laser beam diameter was Ϸ25 m. Graybody temperatures were determined by fitting the thermal radiation spectrum between 670 nm and 830 nm to the Planck radiation function. The tempe...

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Phase transitions of MnO to 137 GPa

Cited by 45 publications

References 19 publications

Electronic Transitions in f-electron Metals at High Pressures:

Electronic Transitions in f-electron Metals at High Pressures:

Stability of the perovskite structure and possibility of the transition to the post-perovskite structure in CaSiO3, FeSiO3, MnSiO3 and CoSiO3

Stability of magnesiowüstite in Earth's lower mantle

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