Adjusting the concentration of free carriers is a direct strategy to achieve ideal negative permittivity.Employing chemical methods for atypical ion doping is an effective approach to regulate the concentration of fre...Adjusting the concentration of free carriers is a direct strategy to achieve ideal negative permittivity.Employing chemical methods for atypical ion doping is an effective approach to regulate the concentration of free carriers.Owing to the A-site tunability of perovskite manganese oxides,doping with multivalent ions becomes particularly favorable.In this study,to realize temperature-stable negative permittivity,mono-phase La_(1-x-y)Ca_(x)K_(y)MnO_(3)(named LCKMO)perovskite crystals having diverse compositions were prepared using an ultra-high-alkaline hydrothermal method.Heterovalent ion doping(La^(3+),Ca^(2+),and K^(+))at the A site within the perovskite crystal structure occurred with the help of the disproportionation reaction of Mn ions at the B site under extreme hydrothermal conditions.By adjusting the La/Ca ratio,we can vary the doping content of K^(+).Experimental results demonstrate that as the concentration of K^(+)increases,so does the concentration of Mn oxide states,indicating that the increase in free carriers contributes to enhanced negative permittivity and reduced dielectric loss.This work thus pioneers a novel synthetic pathway for the creation and design of materials having negative permittivity.展开更多
基金supported by the Natural Science Foundation of Jilin Province No.20240101171JCExperimental Technology Project of Jilin University(SYXM2024a004)+1 种基金Jilin Science and Technology Development Plan Project(SKL202402007)the National Key R&D Program of China(2023YFA1506300).
文摘Adjusting the concentration of free carriers is a direct strategy to achieve ideal negative permittivity.Employing chemical methods for atypical ion doping is an effective approach to regulate the concentration of free carriers.Owing to the A-site tunability of perovskite manganese oxides,doping with multivalent ions becomes particularly favorable.In this study,to realize temperature-stable negative permittivity,mono-phase La_(1-x-y)Ca_(x)K_(y)MnO_(3)(named LCKMO)perovskite crystals having diverse compositions were prepared using an ultra-high-alkaline hydrothermal method.Heterovalent ion doping(La^(3+),Ca^(2+),and K^(+))at the A site within the perovskite crystal structure occurred with the help of the disproportionation reaction of Mn ions at the B site under extreme hydrothermal conditions.By adjusting the La/Ca ratio,we can vary the doping content of K^(+).Experimental results demonstrate that as the concentration of K^(+)increases,so does the concentration of Mn oxide states,indicating that the increase in free carriers contributes to enhanced negative permittivity and reduced dielectric loss.This work thus pioneers a novel synthetic pathway for the creation and design of materials having negative permittivity.
