ABSTRACT
Multiferroic materials are at the core of voltage-controlled spintronic devices. Therefore, an understanding of the underlying electronic correlations and their effects associated with their complex energy landscape is an important and ongoing task. One key parameter in oxide-based perovskite multiferroics is their sensitivity to strain effects under confinement. Here, we report on the ferromagnetism induced by strain-engineering at the nanoscale on BiFeO3 (BFO) nanoparticles. By controlling synthesis parameters, we were able to modify the BFO lattice parameters up to 0.15% and as a consequence, induce ferromagnetism in otherwise antiferromagnetic bulk BFO. In order to understand the driving mechanisms behind such an effect, we performed density functional theory calculations (DFT) using the BFO parameters obtained from the experiment. We found that small distortions of the structural lattice parameters of the order of 0.01% are sufficient to induce a significant spin imbalance close to the Fermi energy at the Fe sites. This may explain the appearance of weak ferromagnetism in strained BFO thin films reported earlier and offers a new route to novel voltage-controlled spintronic devices based on multiferroic materials.
ABSTRACT
El edema pulmonar agudo por presión negativa es una causa importante de edema pulmonar que se desarrolla inmediatamente después de la extubación. Se expone el caso de una paciente con antecedentes importantes de alergia a múltiples medicamentos, programada para colecistectomía laparoscópica que, de manera inmediata, después de la extubación, desarrolló un laringoespasmo que evolucionó a edema agudo de pulmón con insuficiencia respiratoria aguda que requirió ventilación mecánica. El cuadro evolucionó favorablemente y se resolvió en las 72 horas posteriores a la cirugía (AU)
Negative presure pulmonary edema is an important cause of pulmonary edema that takes place inmediately after the extubation. We describe the case of a patient with history of multiple medications allergies. She was admitted outpatient laparoscopic colecystectomy and immediately after extubation she developed a laryngospasm wich envolved acute pulmonary edema with severe acute respiratory failure and she required mechanic ventilation. The patient was discharge after 72 hours (AU)
