Тип публикации: статья из журнала
Год издания: 2013
Идентификатор DOI: 10.1073/pnas.1304827110
Ключевые слова: diamond anvil cell, synchrotron radiation, Mott insulator, spin crossover, ferropericlase, ferrous ion, iron, iron derivative, unclassified drug, acceleration, article, calculation, controlled study, electronics, low temperature, magnetism, Mossbauer spectroscopy, physical chemistry, priority journal, quantum mechanics, synchrotron Mossbauer spectroscopy, theoretical model, transmission electron microscopy
Аннотация: Ferropericlase [(Mg,Fe)O] is one of the most abundant minerals of the earth's lower mantle. The high-spin (HS) to low-spin (LS) transition in the Fe2+ ions may dramatically alter the physical and chemical properties of (Mg,Fe) O in the deep mantle. To understand the effects of compression on the ground electronic state of iron, eleПоказать полностьюctronic and magnetic states of Fe2+ in (Mg0.75Fe0.25)O have been investigated using transmission and synchrotron Mossbauer spectroscopy at high pressures and low temperatures (down to 5 K). Our results show that the ground electronic state of Fe2+ at the critical pressure P-c of the spin transition close to T = 0 is governed by a quantum critical point (T = 0, P = P-c) at which the energy required for the fluctuation between HS and LS states is zero. Analysis of the data gives P-c = 55 GPa. Thermal excitation within the HS or LS states (T > 0 K) is expected to strongly influence the magnetic as well as physical properties of ferropericlase. Multielectron theoretical calculations show that the existence of the quantum critical point at temperatures approaching zero affects not only physical properties of ferropericlase at low temperatures but also its properties at P-T of the earth's lower mantle.
Журнал: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Выпуск журнала: Vol. 110, Is. 18
Номера страниц: 7142-7147
ISSN журнала: 00278424
Место издания: WASHINGTON
Издатель: NATL ACAD SCIENCES