Información del autor
Autor Schmidt, Rainer |
Documentos disponibles escritos por este autor (24)
texto impreso
In this work, the ac admittance of a thick film nickel manganate spinel negative temperature coefficient thermistor ceramic system containing a glass phase is investigated. The dominating relaxation process is a grain boundary (GB) effect and ha[...]texto impreso
The dielectric and magnetic properties and their correlations were investigated in polycrystalline perovskite LaCoO_(3). The intrinsic bulk and grain-boundary (GB) dielectric relaxation processes were deconvoluted using impedance spectroscopy be[...]texto impreso
Pastor, María Jesús ; Cuerva, Cristián ; Campo, José A. ; Schmidt, Rainer ; Torres, María Rosario ; Cano, Mercedes | MDPI AG | 2016-05Ionic liquid crystals (ILCs) allow the combination of the high ionic conductivity of ionic liquids (ILs) with the supramolecular organization of liquid crystals (LCs). ILCs salts were obtained by the assembly of long-chained diketonylpyridinium [...]texto impreso
The influence of sintering temperature and dwell time on the microstructure formation and dielectric properties of CaCu_(3)Ti_(4)O_(12) ceramics was investigated. For sintering temperatures of 1050 and 1100 °C significant differences in the CaCu[...]texto impreso
Frechero, M. A. ; Rocci, Mirko ; Schmidt, Rainer ; Díaz Guillén, M. R. ; Durá, O. J. ; Rivera Calzada, Alberto Carlos ; Santamaría Sánchez-Barriga, Jacobo ; León Yebra, Carlos | Sociedad Española de Cerámica y Vidrio | 2012-01Here we show impedance spectroscopy measurements on a bicrystal of the ionically conducting yttria stabilized zirconia (YSZ). By using micrometer sized electrodes it is possible to measure ionic transport perpendicular to a single grain boundary[...]texto impreso
Schmidt, Rainer ; Basu, A. ; Brinkman, A. W. ; Klusek, Z. ; Datta, P. K. | American Institute of Physics | 2005-02-14The resistance versus temperature (R–T) characteristics of NiMn_(2)O_(4+?) thermistors have been analyzed. In the literature, electron transport in manganate spinels is commonly described by a small-polaron model for nearest neighbor hopping, bu[...]texto impreso
Sánchez Ahijón, Elena ; Marín Gamero, Rafael, Rafael ; Molero Sánchez, Beatriz ; Ávila Brande, David ; Manjón Sanz, Alicia ; Fernández Díaz, M. Teresa ; Morán, Emilio ; Schmidt, Rainer ; Prado Gonjal, Jesús | RSC | 2020-02-14In a recent theoretical study [Jacobs et al., Adv. Energy Mater., 2018, 8, 1702708], BaFe0.125Co0.125Zr0.75O3-delta was predicted to be a stable phase with outstanding performance as an auspicious cathode for intermediate-temperature solid oxide[...]texto impreso
Schmidt, Rainer ; Mayrhofer, Patrick ; Schmid, Ulrich ; Bittner, Achim | American Institute of Physics | 2019-02-26In this work, a comprehensive characterization of metal-insulator-semiconductor structures by impedance spectroscopy is demonstrated for the case of electrically insulating, highly c-axis oriented, 600 nm sputter-deposited AlN films on n-Si subs[...]texto impreso
Schmidt, Rainer ; Eerenstein, Wilma ; Winiecki, Thomas ; Morrison, Finlay D. | American Physical Society | 2007-06-14Temperature dependent impedance spectroscopy enables the many contributions to the dielectric and resistive properties of condensed matter to be deconvoluted and characterized separately. We have achieved this for multiferroic epitaxial thin fil[...]texto impreso
Temperature dependent in-plane impedance spectroscopy measurements were carried out in order to analyze the charge transport properties of functional oxide NiMn_(2)O_(4) negative temperature coefficient thermistor films deposited via aerosol dep[...]texto impreso
In this work, the charge transport properties of charge ordered (CO) La_(1?x)Ca_(x)MnO_(3) (x=0.55,0.67) epitaxial thin films and polycrystals are discussed following the recent controversy of localized electron states versus weakly or delocaliz[...]texto impreso
Cuerva de Alaíz, Cristián ; Campo Santillana, José Antonio ; Cano Esquivel, Mercedes ; Schmidt, Rainer | Royal Society of Chemistry | 2019-09-07Several series of dihalide Pd(II) compounds bearing pyridyl or isoquinolinylpyrazole ligands have been strategically designed and synthesised to exhibit columnar mesomorphism in wide stability ranges. The coordination of the pyrazoles to the fra[...]texto impreso
The dielectric properties of multiferroic BiMnO_(3) 50 nm epitaxial thin films grown on Nb-doped SrTiO_(3)(001) substrates were analyzed by impedance spectroscopy between 55 and 155 K. One single intrinsic thin film dielectric relaxation process[...]texto impreso
In the work presented the magnetic properties of the high pressure ilmenite phase Mn_2FeSbO_6 are investigated in detail. It is shown that Mn_2FeSbO_6 ilmenite is ferrimagnetic (T_N approximate to 270 K) and exhibits a near-zero coercive field H[...]texto impreso
Schmidt, Rainer ; Ventura, Jofre ; Langenberg, Eric ; Nemes, Norbert Marcel ; Munuera, Carmen ; Varela, Manuel ; García-Hernández, Mar ; León Yebra, Carlos ; Santamaría Sánchez-Barriga, Jacobo | American Physical Society | 2012-07The detection of true magnetocapacitance (MC) as a manifestation of magnetoelectric coupling (MEC) in multiferroic materials is a nontrivial task, because pure magnetoresistance (MR) of an extrinsic Maxwell-Wagner-type dielectric relaxation can [...]texto impreso
Prado Gonjal, Jesús de la Paz ; Heuguet, Romain ; Muñoz Gil, Daniel ; Rivera Calzada, Alberto Carlos ; Marinel, Sylvain ; Morán, Emilio ; Schmidt, Rainer | Pergamon-Elsevier Science Ltd | 2015-12-07In this work we report on the combined use of microwave (MW) heating sources for the powder synthesis and the ceramic sintering of Sm and Ca co-doped ceria Ce_(0.8)Sm_(0.18)Ca_(0.02)O_(1.9) polycrystalline materials for potential application as [...]texto impreso
Pastor, María Jesús ; Sánchez, Ignacio ; Campo, José A. ; Schmidt, Rainer ; Cano, Mercedes | MDPI | 2018-04Ionic liquid crystals (ILCs) are a class of materials that combine the properties of liquid crystals (LCs) and ionic liquids (ILs). This type of materials is directed towards properties such as conductivity in ordered systems at different temper[...]texto impreso
A combined powder X-ray lattice parameter and ceramic impedance spectroscopy study is presented on materials within the CaO–CuO–TiO_(2) ternary phase diagram. Several compositions containing CaCu_(3)Ti_(4)O_(12) (CCTO) and small amounts of secon[...]texto impreso
Frechero, M. A. ; Rocci, Mirko ; Sánchez Santolino, Gabriel ; Salafranca, Juan ; Schmidt, Rainer ; Díaz Guillén, M. R. ; Durá, O. J. ; Rivera Calzada, Alberto Carlos ; Varela del Arco, María ; Santamaría Sánchez-Barriga, Jacobo ; León Yebra, Carlos | Nature Publishing Group | 2015-12-17The blocking of ion transport at interfaces strongly limits the performance of electrochemical nanodevices for energy applications. The barrier is believed to arise from space-charge regions generated by mobile ions by analogy to semiconductor j[...]texto impreso
Fiorenza, Patrick ; Lo Nigro, Raffaella ; Raineri, Vito ; Schmidt, Rainer ; Sinclair, Derek | IOP Publishing | 2010Scanning probe microscopy (SPM) with conductive tips has been used to image the dielectric properties of ceramics with giant permittivity. In particular, measurements in impedance mode of local resistivity allowed to image the permittivity map o[...]texto impreso
The temperature dependence of small polaron hopping conduction in ceramic spinel NiMn_(2)O_(4+?) thermistor material has been investigated. We used a theoretical framework based on a random resistor network model to describe small polaron neares[...]texto impreso
Nemes, Norbert Marcel ; León Yebra, Carlos ; Santamaría Sánchez-Barriga, Jacobo ; Tornos Castillo, Javier ; Cuéllar Jiménez, Fabián Andrés ; Beltrán Finez, Juan Ignacio ; Biskup Zaja, Nevenko ; Schmidt, Rainer ; Durán Montejano, Luis ; Ayargüena Porras, Blanca ; Ábalos Álvarez, Marta ; Rodríguez Pérez, Oscar ; Javierre Aso, Ramón ; Hernández Maldonado, David | 2020-04-24El Objetivo General del Proyecto de Innovación “SmartFis” se centraba en facilitar el aprendizaje de los contenidos propios de las múltiples asignaturas impartidas en el Laboratorio de Física General de la Facultad de Ciencias Físicas, en varias[...]texto impreso
The charge transport mechanism and the macroscopic dielectric constant in polycrystalline device materials commonly exhibit several components such as electrode-sample interface, grain boundary and bulk contributions. In order to gain precise un[...]texto impreso
Ramírez, J. G. ; Schmidt, Rainer ; Sharoni, A. ; Gómez, M. E. ; Schuller, Ivan K. ; Patiño, Edgar J. | American Institute of Physics | 2013-02-11Temperature dependent dielectric spectroscopy measurements on vanadium dioxide thin films allow us to distinguish between the resistive, capacitive, and inductive contributions to the impedance across the metal-insulator transition (MIT). We dev[...]