Experimental test of the heating and cooling rate effect on blocking temperatures

doi:10.1093/gji/ggx153

CORC > 地质与地球物理研究所 > 中国科学院地质与地球物理研究所 > 中国科学院地球与行星物理重点实验室

	Experimental test of the heating and cooling rate effect on blocking temperatures
	Berndt, Thomas 1; Paterson, Greig A.2; Cao, Changqian 2,3; Muxworthy, Adrian R.1
刊名	GEOPHYSICAL JOURNAL INTERNATIONAL
	2017-07-01
卷号	210 期号:1 页码:255-269
关键词	Magnetic mineralogy and petrology Palaeointensity Palaeomagnetism applied to geologic processes Rock and mineral magnetism
ISSN号	0956-540X
DOI	10.1093/gji/ggx153
文献子类	Article
英文摘要	The cooling rates at which rocks acquire thermoremanent magnetizations (TRMs), affect their unblocking temperatures in thermal demagnetization experiments; similarly the heating rates at which the thermal demagnetization experiments are done also affect the unblocking temperature. We have tested the effects of variable cooling and heating rates on the unblocking temperatures of two natural non-interacting, magnetically uniform (single-domain, SD) (titano) magnetite samples and a synthetic SD magnetoferritin sample. While previous studies have only considered unblocking temperatures for stepwise thermal demagnetization data (i.e. the room-temperature magnetization after incremental heating), in this work we derive an expression for continuous thermal demagnetization of both TRMs and viscous remanent magnetizations (VRMs) and relate the heating rate to an effective equivalent hold time of a stepwise thermal demagnetization experiment. Through our analysis we reach four main conclusions: First, the theoretical expressions for the heating/cooling rate effect do not accurately predict experimentally observed blocking temperatures. Empirically, the relation can be modified incorporating a factor that amplifies both the temperature and the heating rate dependence of the heating/cooling rate effect. Using these correction factors, Pullaiah nomograms can accurately predict blocking temperatures of both TRMs and VRMs for continuous heating/cooling. Second, demagnetization temperatures are approximately predicted by published 'Pullaiah nomograms', but blocking occurs gradually over temperature intervals of 5-40 K. Third, the theoretically predicted temperatures correspond to similar to 54-82 per cent blocking, depending on the sample. Fourth, the blocking temperatures can be used to obtain estimates of the atomic attempt time t 0, which were found to be 3 x 10(-10) s for large grained (titano) magnetite, 1 x 10(-13) s for small grained (titano) magnetite below the Verwey transition and 9 x 10(-10) s for magnetoferritin (similar to 8 nm).
WOS关键词	SINGLE-DOMAIN GRAINS ; VISCOUS REMANENT MAGNETIZATION ; THERMAL DEMAGNETIZATION ; THERMOREMANENT MAGNETIZATION ; UNBLOCKING TEMPERATURES ; CANCER-CELLS ; SIZE ; DEPENDENCE ; MAGNETITE ; NANOPARTICLES
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	OXFORD UNIV PRESS
WOS记录号	WOS:000409281300018
资助机构	British Research Council, NERC(NE/J020508/1) ; Institute of Rock Magnetism (IRM) ; University of Minnesota ; NSFC(41374072 ; CAS(XDB18010203) ; 41574063) ; British Research Council, NERC(NE/J020508/1) ; Institute of Rock Magnetism (IRM) ; University of Minnesota ; NSFC(41374072 ; CAS(XDB18010203) ; 41574063) ; British Research Council, NERC(NE/J020508/1) ; Institute of Rock Magnetism (IRM) ; University of Minnesota ; NSFC(41374072 ; CAS(XDB18010203) ; 41574063) ; British Research Council, NERC(NE/J020508/1) ; Institute of Rock Magnetism (IRM) ; University of Minnesota ; NSFC(41374072 ; CAS(XDB18010203) ; 41574063)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/61913]
专题	地质与地球物理研究所_中国科学院地球与行星物理重点实验室
通讯作者	Berndt, Thomas
作者单位	1.Imperial Coll London, Dept Earth Sci & Engn, London SW7 2AZ, England 2.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Earth & Planetary Phys, Beijing 100029, Peoples R China 3.Chinese Acad Sci, France China Biomineralizat & Nanostruct Lab, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Berndt, Thomas,Paterson, Greig A.,Cao, Changqian,et al. Experimental test of the heating and cooling rate effect on blocking temperatures[J]. GEOPHYSICAL JOURNAL INTERNATIONAL,2017,210(1):255-269.
APA	Berndt, Thomas,Paterson, Greig A.,Cao, Changqian,&Muxworthy, Adrian R..(2017).Experimental test of the heating and cooling rate effect on blocking temperatures.GEOPHYSICAL JOURNAL INTERNATIONAL,210(1),255-269.
MLA	Berndt, Thomas,et al."Experimental test of the heating and cooling rate effect on blocking temperatures".GEOPHYSICAL JOURNAL INTERNATIONAL 210.1(2017):255-269.