The investigation of new memory circuits is very important for the development of future generations' non-volatile and Random Access Memories (RAM) memories and modern schemes for in-memory calculations. The purpose of the present research is to propose a detailed analysis of passive and hybrid memristor-based memory crossbars with separating metal oxide semiconductor (MOS) transistors. The considered memristors are based on HfO 2 . The transistors are applied to eliminate the parasitic paths in the schemes. For simulations, a previously proposed strongly nonlinear modified window function by the author together with a physical nonlinear memristor model is used. The considered model is adjusted according to the experimental i-v relationship of HfO 2 memristors. The i-v relationship obtained by the simulation is successfully fitted to the respective relationship derived by physical measurements. A good coincidence between these characteristics is established. Several basic window functions are also applied for comparison to the corresponding results. The proposed model is analyzed in Personal Simulation Program with Integrated Circuit Emphasis (PSpice) and it is also used for simulation of a 5 × 5 fragment of a memristor memory crossbar with isolating transistors and for the analysis of a 6 × 6 passive memory matrix. The investigated matrices are simulated for writing, reading, and erasing information. It is established that the model proposed could be used for simulations of complex memristor circuits.In-memory computing with memristors is a very important and valuable technique for future generation's memories and computational circuits [13][14][15]. This paper and a previous one written by the author [16] are associated with in-memory calculation circuits and memory devices based on memristors. The previous paper [16] considers an analysis of the crossbar with four transistors and four resistance-switching memory elements 4T4R matrix with TiO 2 memristors in MATrix Laboratory (MATLAB). The present research is an attempt to analyze memristor crossbars (10T25R) with different types of memristors-HfO 2 -based memory elements, which are modern and important for new engineering applications. This investigation is realized in the PSpice environment by applying different memristor models. An additional comparison between the applied parameters is made. The first physical memristor was created in the Hewlett Packard (HP) research laboratories by Williams's scientific team in 2008 [4]. A number of papers related to memristors and memristive devices have been published and many models have been proposed [5][6][7]9]. The linear dopant drift model [4] is applied for low-level signals. The nonlinear models proposed by Biolek [6] and Joglekar [5] are able to illustrate nonlinear memristor performance for high-level signals and low frequencies according to the state variable [9]. The Pickett model [17] is based on physical measurements, and on the mechanism of the current flow through a tunnel barrier. It has maximal correctn...