Exchange bias effect has been widely employed for various magnetic devices.The experimentally reported magnitude of exchange bias field is often smaller than that predicted theoretically,which is considered to be due ...Exchange bias effect has been widely employed for various magnetic devices.The experimentally reported magnitude of exchange bias field is often smaller than that predicted theoretically,which is considered to be due to the partly pinned spins of ferromagnetic layer by antiferromagnetic layer.However,mapping the distribution of pinned spins is challenging.In this work,we directly image the reverse domain nucleation and domain wall movement process in the exchange biased Co Fe B/Ir Mn bilayers by Lorentz transmission electron microscopy.From the in-situ experiments,we obtain the distribution mapping of the pinning strength,showing that only 1/6 of the ferromagnetic layer at the interface is strongly pinned by the antiferromagnetic layer.Our results prove the existence of an inhomogeneous pinning effect in exchange bias systems.展开更多
An electronic personal dosimeter mainly uses a Si-PIN photodiode as X-and gamma-ray detectors.The photon energy response of this instrument is inconsistent in the case of no correction,which seriously affects the accu...An electronic personal dosimeter mainly uses a Si-PIN photodiode as X-and gamma-ray detectors.The photon energy response of this instrument is inconsistent in the case of no correction,which seriously affects the accurate monitoring of personal dose equivalent H_p(10)parameters for radiation workers.For this reason,in this paper we propose a method of combining composite screen detection technology,multichannel measurement technology,and the channel ratio method to achieve accurate measurement of the personal dose equivalent parameters.According to China National Standard GB/T 13161-2003 and National Verification Regulation JJG 1009-2006,the instrument was tested in the energy range between 48 keV and 1.25 MeV.The experimental results showed that the difference of energy response to ^(137)C_S corrected by the new method was almost constant within ±6.0%,which fulfilled the ±30% requirement of GB/T 13161-2003 and JJG1009-2006.Meanwhile,the method proposed obtained energy information regarding the radiation field.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0201102)the National Natural Science Foundation of China(Grant No.51571208)+3 种基金the Instrument Developing Project of Chinese Academy of Sciences(Grant No.YZ201536)the Program for Key Science and Technology Innovation Team of Zhejiang Province,China(Grant No.2013TD08)the K C Wong Education Foundation(Grant No.rczx0800)the K C Wong Magna Fund in Ningbo University
文摘Exchange bias effect has been widely employed for various magnetic devices.The experimentally reported magnitude of exchange bias field is often smaller than that predicted theoretically,which is considered to be due to the partly pinned spins of ferromagnetic layer by antiferromagnetic layer.However,mapping the distribution of pinned spins is challenging.In this work,we directly image the reverse domain nucleation and domain wall movement process in the exchange biased Co Fe B/Ir Mn bilayers by Lorentz transmission electron microscopy.From the in-situ experiments,we obtain the distribution mapping of the pinning strength,showing that only 1/6 of the ferromagnetic layer at the interface is strongly pinned by the antiferromagnetic layer.Our results prove the existence of an inhomogeneous pinning effect in exchange bias systems.
基金supported by the National Key Scientific Instruments To Develop Dedicated(2013YQ090811)
文摘An electronic personal dosimeter mainly uses a Si-PIN photodiode as X-and gamma-ray detectors.The photon energy response of this instrument is inconsistent in the case of no correction,which seriously affects the accurate monitoring of personal dose equivalent H_p(10)parameters for radiation workers.For this reason,in this paper we propose a method of combining composite screen detection technology,multichannel measurement technology,and the channel ratio method to achieve accurate measurement of the personal dose equivalent parameters.According to China National Standard GB/T 13161-2003 and National Verification Regulation JJG 1009-2006,the instrument was tested in the energy range between 48 keV and 1.25 MeV.The experimental results showed that the difference of energy response to ^(137)C_S corrected by the new method was almost constant within ±6.0%,which fulfilled the ±30% requirement of GB/T 13161-2003 and JJG1009-2006.Meanwhile,the method proposed obtained energy information regarding the radiation field.
