start-ver=1.4
cd-journal=joma
no-vol=53
cd-vols=
no-issue=10
article-no=
start-page=e2025GL121007
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2026
dt-pub=20260512
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Spin Transition of Fe3+ in δ-(Al,Fe)OOH and Implication for Mid-Lower Mantle Seismic Heterogeneities
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=δ-(Al,Fe)OOH is an important water carrier and plays a critical role on Earth's deep water cycle. Lattice parameters of δ-(Al0.89Fe0.11)OOH were measured by synchrotron single-crystal X-ray diffraction at simultaneously high temperature and pressure up to 65 GPa and 800 K in diamond anvil cells. The results reveal that the spin crossover increases from 30 to 37 GPa at 300 K to 36–48 GPa at 700 K. Moreover, at the spin crossover, the KT and VΦ of δ-(Al0.89Fe0.11)OOH occur significant elastic softening, with maximum reductions of 50% on KT and 29% on VΦ at 33 GPa and 300 K to 37% on KT and 23% on VΦ at 41 GPa and 700 K. The anomalous elastic properties of δ-(Al,Fe)OOH at the spin crossover enhance our understanding of local seismic observations anomalies and help identify potential water-rich regions in the mid-lower mantle.
en-copyright=
kn-copyright=

en-aut-name=ZhaoChaoshuai
en-aut-sei=Zhao
en-aut-mei=Chaoshuai
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=MaoZhu
en-aut-sei=Mao
en-aut-mei=Zhu
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=ZhangXinyue
en-aut-sei=Zhang
en-aut-mei=Xinyue
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=YuYingxin
en-aut-sei=Yu
en-aut-mei=Yingxin
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=SunNingyu
en-aut-sei=Sun
en-aut-mei=Ningyu
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=ZhangJianbo
en-aut-sei=Zhang
en-aut-mei=Jianbo
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

en-aut-name=WangYuzhu
en-aut-sei=Wang
en-aut-mei=Yuzhu
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=7
ORCID=

en-aut-name=IshiiTakayuki
en-aut-sei=Ishii
en-aut-mei=Takayuki
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=8
ORCID=

affil-num=1
en-affil=State Key Laboratory of Precision Geodesy, University of Science and Technology of China
kn-affil=

affil-num=2
en-affil=State Key Laboratory of Precision Geodesy, University of Science and Technology of China
kn-affil=

affil-num=3
en-affil=State Key Laboratory of Precision Geodesy, University of Science and Technology of China
kn-affil=

affil-num=4
en-affil=State Key Laboratory of Precision Geodesy, University of Science and Technology of China
kn-affil=

affil-num=5
en-affil=State Key Laboratory of Precision Geodesy, University of Science and Technology of China
kn-affil=

affil-num=6
en-affil=Center for High Pressure Science and Technology Advanced Research
kn-affil=

affil-num=7
en-affil=Shanghai Advanced Research Institute, Chinese Academy of Sciences
kn-affil=

affil-num=8
en-affil=Institute for Planetary Materials, Okayama University
kn-affil=
en-keyword=spin transition
kn-keyword=spin transition
en-keyword=δ-(Al,Fe)OOH
kn-keyword=δ-(Al,Fe)OOH
en-keyword=seismic heterogeneities
kn-keyword=seismic heterogeneities
en-keyword=deep water cycle
kn-keyword=deep water cycle
en-keyword=high temperature and high pressure
kn-keyword=high temperature and high pressure
END