Strongly Coupled Spin Waves and Surface Acoustic Waves at Room Temperature.

Here, we report the observation of strong coupling between magnons and surface acoustic wave (SAW) phonons in a thin CoFeB film constructed in an on-chip SAW resonator by analyzing SAW phonon dispersion anticrossings. We employ a nanostructured SAW resonator design that, in contrast to conventional SAW resonators, allows us to enhance shear-horizontal strain. Crucially, this type of strain couples strongly to magnons. Our device design provides the tunability of the film thickness with a fixed phonon wavelength, which is a departure from the conventional approach in strong magnon-phonon coupling research. We detect a monotonic increase in the coupling strength by expanding the film thickness, which agrees with our theoretical model. Our work offers a significant way to advance fundamental research and the development of devices based on magnon-phonon hybrid quasiparticles.

Acoustically Driven Magnon-Phonon Coupling in a Layered Antiferromagnet.

Harnessing the causal relationships between mechanical and magnetic properties of Van der Waals materials presents a wealth of untapped opportunity for scientific and technological advancement, from precision sensing to novel memories. This can, however, only be exploited if the means exist to efficiently interface with the magnetoelastic interaction. Here, we demonstrate acoustically driven spin-wave resonance in a crystalline antiferromagnet, chromium trichloride, via surface acoustic wave irradiation. The resulting magnon-phonon coupling is found to depend strongly on sample temperature and external magnetic field orientation, and displays a high sensitivity to extremely weak magnetic anisotropy fields in the few mT range. Our work demonstrates a natural pairing between power-efficient strain-wave technology and the excellent mechanical properties of Van der Waals materials, representing a foothold toward widespread future adoption of dynamic magnetoacoustics.

Valley-Selective Phonon-Magnon Scattering in Magnetoelastic Superlattices.

Phonons and magnons are engineered by periodic potential landscapes in phononic and magnonic crystals, and their combined studies may enable valley phonon transport tunable by the magnetic field. Through nonreciprocal surface acoustic wave transmission, we demonstrate valley-selective phonon-magnon scattering in magnetoelastic superlattices. The lattice symmetry and the out-of-plane magnetization component control the sign of nonreciprocity. The phonons in the valleys play a crucial role in generating nonreciprocal transmission by inducing circularly polarized strains that couple with the magnons. The transmission spectra show a nonreciprocity peak near a transmission gap, matching the phononic band structure. Our results open the way for manipulating valley phonon transport through periodically varying magnon-phonon coupling.

Photoinduced Rashba Spin-to-Charge Conversion via an Interfacial Unoccupied State.

At interfaces with inversion symmetry breaking, the Rashba effect couples the motion of the electrons to their spin; as a result, a spin charge interconversion mechanism can occur. These interconversion mechanisms commonly exploit Rashba spin splitting at the Fermi level by spin pumping or spin torque ferromagnetic resonance. Here, we report evidence of significant photoinduced spin-to-charge conversion via Rashba spin splitting in an unoccupied state above the Fermi level at the Cu(111)/α-Bi_{2}O_{3} interface. We predict an average Rashba coefficient of 1.72×10^{-10} eV m at 1.98 eV above the Fermi level, by a fully relativistic first principles analysis of the interfacial electronic structure with spin orbit interaction. We find agreement with our observation of helicity dependent photoinduced spin-to-charge conversion excited at 1.96 eV at room temperature, with a spin current generation of J_{s}=10^{6} A/m^{2}. The present Letter shows evidence of efficient spin charge conversion exploiting Rashba spin splitting at excited states, harvesting light energy without magnetic materials or external magnetic fields.

Hybrid Systems for the Generation of Nonclassical Mechanical States via Quadratic Interactions.

We present a method to implement two-phonon interactions between mechanical resonators and spin qubits in hybrid setups, and show that these systems can be applied for the generation of nonclassical mechanical states even in the presence of dissipation. In particular, we demonstrate that the implementation of a two-phonon Jaynes-Cummings Hamiltonian under coherent driving of the qubit yields a dissipative phase transition with similarities to the one predicted in the model of the degenerate parametric oscillator: beyond a certain threshold in the driving amplitude, the driven-dissipative system sustains a mixed steady state consisting of a "jumping cat," i.e., a cat state undergoing random jumps between two phases. We consider realistic setups and show that, in samples within reach of current technology, the system features nonclassical transient states, characterized by a negative Wigner function, that persist during timescales of fractions of a second.

Nonreciprocal magnetoacoustic waves with out-of-plane phononic angular momenta.

Surface acoustic wave (SAW) can carry phononic angular momentum, showing great potential as an energy-efficient way to control magnetism. Still, out-of-plane phononic angular momentum in SAW and its interaction with magnetism remain elusive. Here, we studied the SAW-induced magnetoacoustic waves and spin pumping in Ni-based films on LiNbO3 with selected SAW propagation direction. The crystal inversion asymmetry induces circularly polarized phonons with large out-of-plane angular momenta so that up to 60% of the SAW power attenuates nonreciprocally controlled by the out-of-plane magnetization component. The SAW propagation direction dependence of the nonreciprocity verifies the crystal origin of the phononic angular momentum, and a chiral spin pumping demonstrates that the circular polarization can control the spin current generation efficiency. These results provide an additional degree of freedom for the acoustic control of magnetism and open an avenue for applying circularly polarized phonons.

Nonreciprocal surface acoustic wave propagation via magneto-rotation coupling.

A fundamental form of magnon-phonon interaction is an intrinsic property of magnetic materials, the "magnetoelastic coupling." This form of interaction has been the basis for describing magnetostrictive materials and their applications, where strain induces changes of internal magnetic fields. Different from the magnetoelastic coupling, more than 40 years ago, it was proposed that surface acoustic waves may induce surface magnons via rotational motion of the lattice in anisotropic magnets. However, a signature of this magnon-phonon coupling mechanism, termed magneto-rotation coupling, has been elusive. Here, we report the first observation and theoretical framework of the magneto-rotation coupling in a perpendicularly anisotropic film Ta/CoFeB(1.6 nanometers)/MgO, which consequently induces nonreciprocal acoustic wave attenuation with an unprecedented ratio of up to 100% rectification at a theoretically predicted optimized condition. Our work not only experimentally demonstrates a fundamentally new path for investigating magnon-phonon coupling but also justifies the feasibility of the magneto-rotation coupling application.

Embarazo posterior a cirugía conservadora del útero ante hemorragia obstétrica postparto. Presentación de un caso / Pregnancy after conservative surgery of the uterus after postpartum obstetric hemorrhage. Presentation of a case

RESUMEN El embarazo es un proceso natural que debe concebirse sin complicaciones; sin embargo, los desenlaces obstétricos fatales en gestaciones previas, son marcadores importantes de un riesgo incrementado de morbimortalidad materna y perinatal en los próximos embarazos. La hemorragia obstétrica posparto es una de las más frecuentes y severas complicaciones del periparto; como una alternativa terapéutica útil en esos casos, el manejo quirúrgico conservador de útero permite mantener la fertilidad en mujeres con paridad no satisfecha, y mejorar su calidad de vida, aunque en muchas ocasiones, por causas diversas, esto no es posible. Se presenta el caso de una paciente de 26 años de edad, con historia obstétrica de tres embarazos, un parto y un aborto (provocado); y el antecedente de complicación obstétrica hemorrágica en embarazo anterior por atonía uterina, la cual requirió tratamiento quirúrgico conservador con técnicas combinadas (suturas compresivas de Hayman, Ho-Cho y ligadura bilateral de las arterias uterinas). Dos años después, acudió a los servicios obstétricos con gestación de 16 semanas (alto riesgo obstétrico). Este artículo tiene el objetivo de exponer el informe de una paciente en la que se logró la concepción de un embarazo posterior a la realización de cirugía conservadora del útero.

ABSTRACT Pregnancy is a natural process that must be conceived without complications; however, fatal obstetric outcomes in previous pregnancies are important markers of an increased risk of maternal and perinatal morbidity and mortality in future pregnancies. Postpartum obstetric hemorrhage is one of the most frequent and severe complications of the peripartum; As a useful therapeutic alternative in these cases, conservative surgical management of the uterus allows fertility to be maintained in women with unsatisfied parity, and improves their quality of life, although in many cases, for various reasons, this is not possible. The case of a 26-year-old patient is presented, with an obstetric history of three pregnancies, one delivery and one abortion (provoked); and a history of hemorrhagic obstetric complication in previous pregnancy due to uterine atony, which required conservative surgical treatment with combined techniques (Hayman, Ho-Cho compression sutures and bilateral ligation of the uterine arteries). Two years later, she attended obstetric services with a 16-week gestation (high obstetric risk). This article aims to present the report of a patient in whom the conception of a pregnancy was achieved after performing conservative surgery on the uterus.

Caracterización clínica de pacientes con morbilidad materna extremadamente grave y su repercusión perinatal. Cienfuegos 2016-2018 / Clinical characterization of patients with extremely severe maternal morbidity and its perinatal impact. Cienfuegos 20016-2018

RESUMEN Fundamento: Estudios realizados dentro y fuera de Cuba demuestran que existe una alta repercusión en la salud del producto de la concepción de madres con morbilidad materna extremadamente grave. Un análisis de esta problemática podría revertirse en una adecuada atención médica y en el logro de resultados perinatales de excelencia. Objetivo: caracterizar a las pacientes con morbilidad materna extremadamente grave y su repercusión perinatal. Métodos: estudio descriptivo, de serie de casos, realizado en el Hospital Dr. Gustavo Aldereguía Lima, de Cienfuegos. La serie estuvo conformada por 145 pacientes con morbilidad materna extremadamente grave, y sus productos de la concepción, atendidos durante el periodo 2016-2018. Se analizó tipo de parto, causas de ingreso, morbilidad materna y neonatal, mortalidad perinatal, entre otras variables. Resultados: predominaron las pacientes sin comorbilidad, no nulíparas y con edad entre los 20 y 34 años. Las causas más frecuentes de ingreso fueron la enfermedad hipertensiva del embarazo (37,9 %) y la hemoragia obstétrica mayor (30,3 %); así como en las terapias neonatales, lo fueron el síndrome de distrés respiratorio (42,5 %) y la asfixia neonatal (400 %). Se observó, además, razón de una paciente con morbilidad materna extremadamente grave por cada 87,4 nacimientos; una muerte materna por cada 72,5 pacientes; y un recién nacido con morbilidad neonatal cada 3,6 pacientes. Conclusión: la morbilidad materna extremadamente grave es una condición de alta repercusión sobre la morbimortalidad perinatal.

ABSTRACT Background: Studies carried out inside and outside of Cuba show that there is a high impact on the health of the product of conception of mothers with extremely serious maternal morbidity. An analysis of this problem could be reverted to adequate medical care and the achievement of excellence perinatal results. Objective: to characterize patients with extremely severe maternal morbidity and its perinatal repercussion. Methods: descriptive study, of a series of cases, carried out at the Dr. Gustavo Aldereguía Lima Hospital, in Cienfuegos. The series consisted of 145 patients with extremely severe maternal morbidity, and their products of conception, treated during the period 2016-2018. Type of delivery, causes of admission, maternal and neonatal morbidity, perinatal mortality, among other variables were analyzed. Results: patients without comorbidity, non-nulliparous and aged between 20 and 34 years predominated. The most frequent causes of admission were hypertensive disease of pregnancy (37.9%) and major obstetric hemorrhage (30.3%); as well as in neonatal therapies, they were the respiratory distress syndrome (42.5%) and neonatal asphyxia (400%). In addition, the ratio of one patient with extremely severe maternal morbidity for every 87.4 births was observed; one maternal death for every 72.5 patients; and one newborn with neonatal morbidity every 3.6 patients. Conclusion: extremely severe maternal morbidity is a condition with a high impact on perinatal morbidity and mortality.

Aplicación del Balón de Bakri ante hemorragia obstétrica postparto. Presentación de un caso / Application of Bakri's Balloon to postpartum obstetric hemorrhage. Case Presentation

RESUMEN La hemorragia obstétrica pos parto complica el 10,5 % de los nacimientos a nivel mundial y está relacionada con una elevada morbimortalidad perinatal. El manejo de esta complicación abarca el tratamiento médico y de ser refractario, habrá que recurrir a un tratamiento quirúrgico basado en taponamiento endouterino con gasas o balón, suturas compresivas uterinas, devascularización pelviana y la embolización arterial. Si todos estos procedimientos no tuvieran efectividad, entonces hay que realizar un tratamiento radical como la histerectomía obstétrica. Se presenta un caso de una gestante 37.5 semanas, nulípara, atendida en el Hospital Dr. Gustavo Aldereguía Lima de Cienfuegos. Se le induce el parto por rotura prematura de membranas, que evoluciona hacia la fase activa y se decide realizar parto instrumentado por fórceps para abreviar período expulsivo por variedad no fisiológica y alteración del bienestar fetal. Se extrae recién nacido femenino con peso de 4025 g, diagnosticándose hemorragia obstétrica mayor por atonía uterina, que no resuelve con el tratamiento médico convencional y se decide realizar manejo conservador del útero mediante compresión endouterina con balón de Bakri. Se logra contractilidad uterina y una evolución clínica satisfactoria. Este procedmimento quirúrgico se describió por primera vez a nivel mundial desde finales del siglo XX y es introducida en Cuba en el año 2016. La provincia de Cienfuegos ha implementado desde entonces estas prácticas conservadoras, logrando en el caso referido reducir la hemorragia, disminuir la morbimortalidad obstétrica y conservar la fertilidad en pacientes con paridad no satisfecha.

ABSTRACT Obstetric hemorrhage after delivery complicates 10.5% of births worldwide and is related to high perinatal morbidity and mortality. Its management includes medical treatment and if refractory, it will be necessary to resort to a surgical treatment based on uterine tamponade with gauze or balloon, uterine compression sutures, pelvic devascularization and arterial embolization. If all these procedures are not effective, then a radical treatment such as obstetric hysterectomy should be performed. The case of a 37.5 week, nulliparous pregnant woman, attended at the Dr. Gustavo Aldereguía Lima Hospital in Cienfuegos is presented. Labor is induced due to premature rupture of membranes that evolves into the active phase and it is decided to perform instrumental delivery by forceps to shorten the expulsive period by non-physiological variety and alteration of fetal well-being. A female 4025 g weight newborn was obtained, with greater obstetric hemorrhage due to uterine atony, which does not resolve with conventional medical treatment and it was decided to perform conservative management of the uterus by means of Barki´s balloon uterine compression. Uterine contractility and a satisfactory clinical evolution are achieved. This surgical procedure was first described worldwide by the end of the 20th century and was introduced in Cuba in 2016. Since then, the Cienfuegos province has implemented these conservative practices. In the case presented it was possible to reduce bleeding. In addition it reduces obstetric morbidity and mortality and preserves fertility in the patient with unmet parity.