ABSTRACT
Manipulating magnetization via power-efficient spin-orbit torque (SOT) has garnered significant attention in the field of spin-based memory and logic devices. However, the damping-like SOT efficiency (ξDL) in heavy metal (HM)/ferromagnetic metal (FM) bilayers is relatively small due to the strong spin dephasing accompanied by additional spin polarization decay. Furthermore, the perpendicular magnetic anisotropy (PMA) originating from the HM/FM interface is constrained by the thickness of FM, which is unfavorable for thermal stability in practical applications. Consequently, it is valuable to develop systems that not only exhibit large ξDL but also balance thermal stability. In this work, we designed antiferromagnetic-coupled [Co/Gd]N multilayers, where staggered Co and Gd magnetic moments effectively suppress the spin dephasing and additional spin polarization decay. The ordered Co-Gd arrangements along the out-of-plane direction provide bulk PMA, endowing Pt/[Co/Gd]N high thermal stability. The SOT of Pt/[Co/Gd]N was systematically studied with N, demonstrating a significantly large ξDL of up to 0.66. The ξDL of Pt/[Co/Gd]N is greater than those of Pt/Co and Pt/ferrimagnetic alloys. This significant enhancement relies on the effective suppression of spin dephasing in [Co/Gd]N. Our work highlights that the antiferromagnetic-coupled [Co/Gd]N multilayer is a promising candidate for low-consumption and high-density spintronic devices.
ABSTRACT
BACKGROUNDS AND OBJECTIVES: The present study was designed to define a novel algorithm capable of predicting female adolescents' cervical vertebrae maturation stage with high recall and accuracy. METHODS: A total of 560 female cephalograms were collected, and cephalograms with unclear vertebral shapes and deformed scales were removed. 480 films from female adolescents (mean age: 11.5 years; age range: 6-19 years) were used for the model development phase, and 80 subjects were randomly and stratified allocated to the validation cohort to further assess the model's performance. Derived significant predictive parameters from 15 anatomic points and 25 quantitative parameters of the second to fourth cervical vertebrae (C2-C4) to establish the ordinary logistic regression model. Evaluation metrics including precision, recall, and F1 score are employed to assess the efficacy of the models in each identified cervical vertebrae maturation stage (iCS). In cases of confusion and mispredictions, the model underwent modification to improve consistency. RESULTS: Four significant parameters, including chronological age, the ratio of D3 to AH3 (D3:AH3), anterosuperior angle of C4 (@4), and distance between C3lp and C4up (C3lp-C4up) were administered into the ordinary regression model. The primary predicting model that implements the novel algorithm was built and the performance evaluation with all stages of 93.96% for accuracy, 93.98% for precision, 93.98% for recall, and 93.95% for F1-score were obtained. Despite the hybrid logistic-based model achieving high accuracy, the unsatisfactory performance of stage estimation was noticed for iCS3 in the primary cohort (89.17%) and validation cohort (85.00%). Through bivariate logistic regression analysis, the posterior height of C4 (PH4) was further selected in the iCS3 to establish a corrected model, thus the evaluation metrics were upgraded to 95.83% and 90.00%, respectively. CONCLUSIONS: An unbiased and objective assessment of the cervical vertebrae maturation (CVM) method can function as a decision-support tool, assisting in the evaluation of the optimal timing for treatment in growing adults. Our novel proposed logistic model yielded individual formulas for each specific CVM stage and attained exceptional performance, indicating the capability to function as a benchmark for maturity evaluation in clinical craniofacial orthopedics for Chinese female adolescents.
