Simultaneous composition and valence-dependent strain regulation is achieved in lead-free(Bi_(0.5)Na_(0.4)K_(0.1))_(1-2x)Sm_(2x)Ti_(1-x)Mn_(x)O_(3)(BNKT-SM100x)ceramics by a facile co-doping design with Sm^(3+)and Mn^...Simultaneous composition and valence-dependent strain regulation is achieved in lead-free(Bi_(0.5)Na_(0.4)K_(0.1))_(1-2x)Sm_(2x)Ti_(1-x)Mn_(x)O_(3)(BNKT-SM100x)ceramics by a facile co-doping design with Sm^(3+)and Mn^(2+).By simply controlling the sintering temperature,Mn ions exhibited mixed-oxidation states with different ion radius and electronic structures,further adjusting the crystalline field.The regulated disorder degree finally induced large electro-strain(0.445%)under appropriate doping contents(x=0.01)and sintering temperature(1150℃).Moreover,the random effect of Mn^(2+)(arising from the different valence and radius comparing with Ti^(4+))is stronger than the pinning effect due to the suppressed oxygen vacancies,and the different crystal structures may also affect the role of Mn^(2+).The domain morphologies with mixed nanodomain and ferroelectric domain were observed in the BNKT-SM1 ceramics,further demonstrating the coexistence of random effect and pinning effect.It is believed that the self-strain regulation phenomenon in this work may serve as an effective strategy for designing ferroelectrics with high strain performance.展开更多
In this paper, an overview of the theory of Mössbauer effect is covered, and the main hyperfine interactions parameters which affect the shape of the resultant Mössbauer spectrum are explained and il...In this paper, an overview of the theory of Mössbauer effect is covered, and the main hyperfine interactions parameters which affect the shape of the resultant Mössbauer spectrum are explained and illustrated as well. In principle, Mössbauer effect applies to any and all nuclides, but in practice, certain ideal properties are desirable;that is, the conditions for recoil-free emission and absorption of gamma rays must be optimized. Therefore, briefly discussed in this review, one of the most commonly used for practical and fundamental studies the 151Eu Mössbauer isotope. Also, the intermediate valence phenomena and their theoretical treatments are briefly discussed.展开更多
基金Authors acknowledge the support of the National Science Foundation of China(No.51972215)。
文摘Simultaneous composition and valence-dependent strain regulation is achieved in lead-free(Bi_(0.5)Na_(0.4)K_(0.1))_(1-2x)Sm_(2x)Ti_(1-x)Mn_(x)O_(3)(BNKT-SM100x)ceramics by a facile co-doping design with Sm^(3+)and Mn^(2+).By simply controlling the sintering temperature,Mn ions exhibited mixed-oxidation states with different ion radius and electronic structures,further adjusting the crystalline field.The regulated disorder degree finally induced large electro-strain(0.445%)under appropriate doping contents(x=0.01)and sintering temperature(1150℃).Moreover,the random effect of Mn^(2+)(arising from the different valence and radius comparing with Ti^(4+))is stronger than the pinning effect due to the suppressed oxygen vacancies,and the different crystal structures may also affect the role of Mn^(2+).The domain morphologies with mixed nanodomain and ferroelectric domain were observed in the BNKT-SM1 ceramics,further demonstrating the coexistence of random effect and pinning effect.It is believed that the self-strain regulation phenomenon in this work may serve as an effective strategy for designing ferroelectrics with high strain performance.
文摘In this paper, an overview of the theory of Mössbauer effect is covered, and the main hyperfine interactions parameters which affect the shape of the resultant Mössbauer spectrum are explained and illustrated as well. In principle, Mössbauer effect applies to any and all nuclides, but in practice, certain ideal properties are desirable;that is, the conditions for recoil-free emission and absorption of gamma rays must be optimized. Therefore, briefly discussed in this review, one of the most commonly used for practical and fundamental studies the 151Eu Mössbauer isotope. Also, the intermediate valence phenomena and their theoretical treatments are briefly discussed.
基金Supported by basic research foundation of northwestern polytechnical university,and postgraduate starting seed foundation of northwestern polytechnical university (Z2010009)~~
